Are the stunts staged or spontaneous?

Through the years of watching Jack-Ass, I've always wondered about some of the stunts they do. A few come to mind

When one of the guys goes into a hardware store to...use one of their display toilets.
When Johnny Knoxville goes into a motor cycle shop (in the old man costume) and then floors it through the front display window.

Were these really staged as shown (taking everyone by surprise) or did someone at the place of business know about it and give consent? If they gave consent, what incentives do they get for letting the show disrupt and possibly destroy their place of business?