I would say that more then half of the tournaments in Vegas that I've cashed in have chopped in some way.
Most of the chops are straight splits. Occasionally chip stacks will dictate a 40/30/30 or similar slight tweak. But it always occurs when everyones stack size vs blind size makes everyone feel vulnerable to random chance.
Usually the table will have been in the shove or nothing phase for while. someone gets busted, bumping all the payout. It gets brought up and every says sure. A tournament like the 1 o'clock at the Aria has been playing for 6+ hours at this point. If it had 100ish entries, It's been a shove fest since there were 2 tables. When it gets down to 4 people, most are eager to just be done with it.
It doesn't get brought up when someone has a dominate lead. At least I haven't seen that. In that case, I imagine it would get rejected.
Although I have no first hand knowledge. I've heard that chops in the WSOP were common before TV coverage. When the organizers realized it would be bad TV to have a chop, it was discouraged.