Well when bringing the shopping in, and the kids ask where to put the packet of toilet paper, I don't want to tell them to put it in the toilet because then I'll find it floating later ... but I do tell them to put it in the "toilet room".
Also - when asked "Where is <somebody>?" and they are using the toilet, the polite response is to mention that they are in the "bathroom". However, when it is pointed out that the bathroom is empty it is automatic to clarify that they are in the "toilet room". They are not "in" the "toilet". The obvious thought would be to say that they are "on" the toilet, but if the person in question is male this might not be true either.