Miriam of Miriam’s Ideas worries about this because of a family connection:
“One of my relatives who travels extensively has not bought soap in 20 years. Apparently the complimentary soaps he takes from hotel rooms fulfill the sanitary needs of his entire family.”
It’s a common behavior, apparently, since her post has drawn scores of hits, including mine. I always swiped the soaps when I traveled but I’d prefer to buy soaps than travel
Via Miriam’s Ideas.
THE TEXAS SCRIBBLER 
Mostly, though, those little bars are fonky types of soap. Not my preference, anyhow.
Depends on the hotel/motel. The perfumy stuff I always left behind.