I bought a small UV flashlight (a.k.a. pee stain detector) from
Amazon when they had it on sale for $4.99(with free 2-day
Prime shipping)


This one: (note: this is not an endorsement or offer to
sell this product.... proceed at your own risk)

It was the worst decision I've ever made. I bring it with me when I fly
and airplane lavatories scared the crap out of me. Holy cow... do people
now know how to aim? What scared me even more was the there were
pee stains on the sink and area around it. Do guys pee into the lavatory
sinks? Now I bring disposable gloves when I fly so I can avoid touching
any surface inside the lavatory. Now I know what it feels like to be
Howie Mendell.



The pee stain detector also caused many sleepless nights in hotels.
I've seen pee stains on beds, couches, desks, corners, toilet tank,
bath tubs, coat hangers, windows.... and once even inside the minibar
refrigerator!!!!!