They Say What They Say

Definitely gross but I've met a few guys who've have done the same. My ultimate was the guy I had sex with in his car outside my folks house in my early 20s - he threw it out the door and it sat in the gutter for me to notice the next day. Bright red, used condom - pretty hard to miss. What a prize he wasn't.

I dunno that I'd discount a guy for leaving it on the bedside table in a strange house....maybe you're already ambivalent about hims and looking for reasons? But single men do generally have different standards of cleanliness to single women.