He would have been noticed immediately.

There is no chance that "got away" with anything by "faking instrument skills."

The marching is NOT basically just "follow the leader."

If he was a warm body and was willing to learn the shows then I'm sure they just let him march along even though he sucked at whatever instrument he was allegedly playing.

He might as well have just said he accidentally joined a synchronized swimming team and no one noticed him because he just followed along.

That's just dumb.