Sorry, was in a bit of a rush this morning, and wasn't as clear as I normally prefer.
Re: Scene Aspect
Yes indeed, it is possible to Compel Aspects in a handful of situations outside of Character Aspects. However, even within the rules they're a bit hamfisted (burning building example) or involve magic (love potion). While you could do it with a Compel... there's probably a much better way.
Re: Aspect from another NPC
A true Compel from another character requires them to pay your character a Fate Point, otherwise it's a Maneuver.
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However, special case or not, yes you're most correct - they're still implied to be "Compels" off situation relevant Temporary Character Aspects (in the rules I believe they use the verbiage "temporarily on your record sheet" even) a but that also means they're negotiated if they're Compelled. That was the essential thrust I was trying to make in my reply this morning.
One of the things mentioned by Locnil in an earlier reply (what lead to me replying myself) - it was an interesting word choice - "Railroaded" specifically in reference to Compels, it makes me wonder if some of the resistance to Compels comes from forgetting (or general inflexibility on) that point.
Today In the Village of Exampleton
We have OPHs (Our Plucky Heroes) facing off against EBGs (Evil Bad Guys) and the GM hits the scene with the Scene Aspect "Tempers Are Running Hot" ... by the very nature of Scene Aspects, the GM is taking a direct hand, but that doesn't mean it has to be a complete railroaded cludge.
Meh - GM Compels the scene Aspect, gives everybody a Fate Point, and combat ensues. Yes, technically within the rules, but I would say this is about as clunky a method as possible. If this is the type of GM style in discussion, I would understand feeling railroaded.
Better - Young Jack, a member of OPH, has the Character Aspect 'a hothead' - the GM Compels THAT and justifies it due to the Scene Aspect "Tempers Are Running Hot" ... it stands to reason a character with a Character Aspect like that would "lose it" in a socially stressful situation and start the combat. However, it would still probably feel a bit like railroading without negotiation.
Fuego! - Young Jack is 'a hothead' and the GM offers a Fate Point for a Compel off it in the Scene. The player of Young Jack doesn't want OPH to "throw the first punch" and would rather have the EBGs start it off so they can claim self-defense later. The GM indicates that he wants fighting to start in exchange for the Fate Point, but Young Jack's player doesn't want to be the one to start it out (for whatever plot reason). So the agreed upon Compel is that Young Jack will use an Intimidation skill attack (off the Provocation trapping) against some chosen member of the EBGs (Fred). So he yells out to Fred, "Hey Fred, is ya sister able to walk straight yet? Heard she got a right propa shaggin' last weekend!" ... Intimidation resisted by Discipline, Young Jack is tagging the Scene Aspect "Tempers Are Running Hot" ... and the player asks the GM if this acceptable for the Compel? GM says it is; gives the Fate Point. Jack inflicts a Great 4 Shift Social Attack after the dice rolls - Fred only has 3 Social Stress so it takes him out (he's really just a minor goon in the scene, no need to take consequences). Young Jack's player says the terms of the "take out" is that Fred makes the first attack, charging across the space between the two groups and takes a swing at Jack.... fight's on. GM's goal met, player still had control of how that Compel played out.
If the player still refused to take the bait, his 'hotheaded' character, in a situation where 'tempers are running hot' ... still didn't lose his temper and kept a lid on it. Very uncharacteristic considering the scene... thus it costs a Fate Point to buy off the GM Compel.
Conceptually related are temporary Character Aspects as what might be applied by something like Bob's Love Potion (independent of a Maneuver Aspect inflicted by another character)
Last Week In Exampleton
Jack (OPH) is on a date with Fred the EBG's Sister. They're out under the stars drinking some homemade wine and discussing whatever it is they talk about in Exampleton... how to grow a turnip or whatever.
A fairy apparently put a Love Potion in Jack's drink. As indicated for the item description, he takes the Aspect "Consumed By Lust..."
Meh - the GM compels it and the scene plays out as one might expect. Yeah, that would feel like railroading.. but then again, it was magic. Young Jack's player is left with the smarmy feeling that maybe his character just got magicked into being the village rapist.
Better - Pretty tough to put a middle of the road lipstick on this pig, but here goes. Player asks what the terms of the Compel are, and that it's Jack must act on his lust in some way that makes it very clear - at least a painfully social awkward situation at the minimum. Jack shuffles/scoots far closer than propriety would allow, and even places his hands on Fred's sister in an unacceptably familiar way (unless they were already intimately acquainted) and risks at least a good cheek slapping at the minimum. Young Jack's player also indicates that if Fred's Sister has any alertness whatsoever, it's easy for her to tell that Young Jack is very ... enamored ... of the situation due to the effects of the lust potion. Socially awkward yes with no idea how the scene will play out, but his character isn't a rapist. The Compel has been acknowledged and acted upon.
Fuego! - Ok, GM's being a right propa git with this scene so might as well own it. Player accepts the Compel and turns around and uses the Fate Point gained to Invoke his Aspect "Right Charming Bloke" to boost a Rapport vs Discipline Seduction attempt. He rolls well enough to overcome Fred's Sister's Social Stress track even though it's technically not an attack - so the scene fades to black as Jack and Fred's Sister enjoy a romantic interlude.
... likely the events of the above led to the conflict I used in the first example.
Tune in next week for the next exiting episode of "As The Butter Churns" ... will Fred's Sister discover she's pregnant? Will Young Jack survive the encounter with Fred's gang?
Hopefully the above shows that a Compel need not feel like "railroading" ... if it does... your group may not be leveraging the system as fully as you otherwise could be. Likewise, hopefully it shows why "buying off" a Compel costs a Fate Point. If the scene is set up properly ... actually going against the trappings of the scene should represent a fairly monumental decision to not engage or participate (thus costs the FP).