Dave Lavery used this logic in a different
thread , and I think it applies here. What you bring to an event is what counts as your spares. If you bring a whole robot, even if you don't bring it in, it's all a spare and all illegal. If you don't bring anything to the event, then you don't have any spares. If you say 254 brought it for 22, then 254 should never be able to use it and it shouldn't even be in their pit tempting them.
EDIT: I think the real problem is the lack of guidance from FIRST on the legality of collaborating and teams trading parts at regionals.