Do not, and I mean never, ever, pay someone at the scene of an accident. Just don’t do it. Nothing good will come from it. A few situations:
A – You pay someone for “minor damage.” You don’t have them sign anything. It turns out that there was more damage. You are going to be stuck for the additional damage.
B – You pay someone for damage. They wake up the next morning and are in pain. They go to the doctor. Your payment to them can be used as an admission of fault.
The only time someone should be paid for an accident is if the paying party receives a full release. Unless you carry these with you, do not pay someone at the scene of an accident!