Those of us who worked and camped at the Renaissance Faire (yeah yeah I'm a dork) used separate port-a-potties from the big public banks of them. The ground was uneven, so they sometimes put them on pallets, which aren't really strong enough and they still rocked. One night a very large guy (about 400 pounds) sat down in one and the pallet broke and the whole thing FELL over backwards. Not happy.
Oh, but portapotties CAN be tipped. They can also be tied onto the back of a Triumph TR-6 and transported to someone's front yard (not my yard, not my TR-6). When I was in college, I attended a toga party and one of my least favorite people (her toga was sparkly...get the picture?) went into the portolet. She'd said something snarky just a few minutes before and so several guys didn't tip it...but instead just sloshed it violently so that she came out with a BLUE sparkly toga (and a hissy fit worth watching!)
varnes- porti-potties are WAY harder because the weight of the sanitizing liquid (and whatever other $hit) is part of the one piece plastic unit..heavy with a high center of gravity. a normal height pick-up can push it but not tip it..(plus most of them are rented and on designated construction sites-too criminal for a prank).. one time though there was an obnoxioux superintendant who always left his keys in his truck..some anonymous person backed the truck up against the p-pottie door while he was in it,turned it off and walked away
My usual response is, "Okay, trick."
Not only do most kids not come prepared, I'm continually surprised at how many don't seem to know what I'm talking about.
Some of us actually remember outhouses. I never tipped any over, but remember the story of one guy who got tired of kids tipping his every Halloween, so one time he moved it back a few feet. There were some shoes left behind the next morning. No one wanted to ever retrieve those shoes.