That's why you get a female cat. Accidents are very rare and basically never on purpose after their potty trained. Unlike a male which marks territory. I've always had both cats and dogs in my house my whole life. Occasionally if we accidentally locked them inside or there was crazy weather or coyotes around and they really had to go, they went in the bathtub without instruction. "Oh... That's OK I guess. Better than anywhere else. Sorry we locked you in." Sometimes the pet doors would be locked due to racoons and opossums. Thinking we were sharing food. Unlocking slips the mind sometimes.