Yes, I'm sure an aileron roll or a gentle barrel roll in most aircraft would be doable without too much drama - the major problems that arise as I see it, though, are:
a) If you stuff it up and exceed the limits while recovering, you've done something to the airframe you're not supposed to, and you may have damaged it.
You're hardly going to go back to the engineers and say 'Oh, I was deliberately exceeding flight manual limits and may have stuffed the aircraft, could you please inspect it?'.
Nope, you'd most likely skulk off as if nothing had happened, in the worst case maybe leading to some tragic occurence like the one stevef mentioned;
b) If you get found out you could do your licence; and
c) If you get found out and damage the aircraft, the insurance company is going to come after you in a big way.