Re: Would it bother you if..
Nope, I never invite my family over for birthdays, they just come. The ONLY time I get incredibly annoyed is when they call me the day before or day of and tell me they're coming over....now. I don't just drop my plans for them, but they're driving far, so I have to make it work somehow with no notice....that' the only reason I get mad. And maybe I would at the uninvited guest? I would probably let him know that we only have space for one and/or he'll need to rent a car since ours wont fit him and we planned to go to x,y,z that week.