All the time, I have allergies and the bathroom is usually a good place to get a good nose blowing done without people being grossed out and I'm about to wash my hands afterwards anyway.
I have done the opposite as well due to carrying a bunch of tissue at all times due to said allergies. Whoops public restroom no TP no seat cover, no problem just pull out a couple of the nice 3-ply tissues I carry and I'm good.