No one even knows if the guy IS naked behind the tarp. All anyone can see are his legs from below the knee and his feet in sandals. As to explaining to kids why he's showering in the parking lot, how about the truth "I don't know, maybe he's homeless or something". I don't know any kid who would be so traumatized by seeing a pair of bare legs as suggested by this thread.
I really doubt his video is going to cause thousands of folks to start showering in Walmart parking lots, therefore banning overnight stays.