>The only actions which cannot overcome a block are the actions that are not impeded by the block.
True, bypassing a block instead of overcoming it doesn't destroy the block. It can make it irrelevant though. I also think you are vastly underestimating the ways a block can be overcome. The action is "to move" if the block is "against movement". The skill used "to move" depends on the nature of the block.
So in my example above (Rapport block against movement) you could destroy the block with something like Intimidate (make the bystanders back off), Rapport (explain you're in a hurry without offending them), Presence (have the crowd move with you in an organized way, or somehow get them to cooperate based on who you are) or Deceit (create a distraction that is more interesting to the crowd than you). Even Perform might get it done under some circumstances (moving through a dance floor, weaving the crowd into your performance and disrupting the block). Resources too under some circumstances (toss money into a crowd of beggars, briefly dispersing them). Contacts might allow someone in the crowd to rescue you with their own social skills.
Or if you were Molly you could leave an image of yourself to engage with the crowd while sneaking off under a veil. The block's still there (crowd of people interested in image-Molly) but Molly bypassed it without destroying it, because she rendered it irrelevant to "invisible Molly".
All of the above assumes some kind of aspect where you care what the crowd thinks, and your reputation. That kind of block on a Ghoul might be a discipline check to avoid feeding on the crowd instead of moving, for example, because of its Insatiable Hunger aspect instead of, say, Murphy's police lieutenant aspect vs a crowd of reporters. A lot of blocks seem to tie into either scene aspects or personal aspects, and I'm not clear on whether they must be tagged/invoked to set up the block. I think the way it works is a true compel gives the individual a fate point for automatically failing to move, where setting up a block doesn't use the fate economy but instead allows a chance to succeed, against an obstacle set by the block.
A more mundane example....critters bypass the zonewide version if Harry's shield spell all the time by going around or over it. The shield spell is still there, blocking anyone else from moving through it, but it doesn't stop a critter that can fly over it from menacing those behind it. If Harry explicitly makes it a bubble to prevent such tricks, then his own people are also affected by the block, or not protected by the block.
More typically Harry's shield is only a block against attacks, and doesn't impede movement of the enemy at all. Either way though, the method to bring down the block is generally to attack it with sufficient force (might, or a physical attack of some kind) even though in one case it is blocking movement and in the other it is blocking attacks. It's still a wall of magical force. The means of defeating it are usually the same regardless of what you're blocking with it. Harry's hand got burned when Mavra bypassed it with pure heat...the block was not overcome, it was irrelevant to Harry because his hand had to be close to the wall, but everybody else was safe, because the napalm that contained the heat was blocked successfully. When Harry redefined the shield to include heat energy (he is, after all, a master of Fire as well as Spirit), it still had some gaps in the coverage to other exotic attacks because it is defined as a shield of force (eg, it won't help if the ground reaches up to grab him, or somebody sucks all the air out of the area of he has not explicitly set it up as a bubble).
