Fun fact: those ball pits *were* cleaned.
At the bottom of each put was a drain hole. Once a year the pit would be filled with hot soapy water, balls stirred with a mop, and then drained
Doing this would turn the pit into Satan's own soup bowl: glistening slicks of body oil and tangles of hair and lost pieces of french fries and such.
Employees were supposed to skim this shit off the top, but usually didn't bother. That's what grease traps are for, right
Ok that's better than expected but that doesn't sound good enough still
I got staph in a tube based play ground once, left a decent, shallow Crater on my face