All's Well That Ends Well

I don't get it: why do so many "musicians" assume a fermata on a long final note when there is none? Why do they stop counting when they reach that last note? It amazes me how this phenomenon affects the entire band, as if everyone is waiting for someone else to stop first. This seems counterintuitive to me; I would think that being the first to cut off would be much less risky than being the one holding on when everyone else has cut off.

A whole note tied to a dotted half gets 7 beats no matter where it occurs - but especially at the end of the song when there's not a birdseye in sight. Count, listen, and have some confidence in your own performance.