I think it depends on the type of sponsored magic. I can see a good argument for Seelie/Unseelie sponsored magic not disrupting technology (accidentally at least) IF it is external. I can also see someone making a character that has that "sponsored" magic, but it is an internal aspect of themselves. If they are a Changeling whose mother was Lea, for instance, then they could well have innate magical abilities, but those abilities are inherently connected to the winter aspect of their nature. Mechanically, this would work a LOT like the sponsored magic the Winter Knight might possess, but there could easily be some subtle differences. Technically, I suppose the rules don't have anything saying you can do this, but since that's a pure flavor aspect, I don't see how it matters.
On the other hand, unless I missed something you can have backlash and the like from any sort of sponsored magic. That means it isn't always well controlled. It is also governed by YOUR skills, indicating that it is your will controlling a good bit of it, however you got access. Seems to me that implies inadvertent hexing.