My 10 month has been house trained for ages. For some reason he has gone to the toilet when he has gotten into my niece or nephew's room. They are usually closed and so it is easily managed. He did it once in my bedroom when he wasn't used to going in, but now he goes in all the time he hasn't done it since. He sometimes goes to doggy day care and has had an accident there. Is it a way of marking?? I'm going to a holiday home and don't want him to have accidents there. It seems strange when he doesn't ever do it in the rest of the house. Thanks.