Ive done this a couple of times and I think you'd be unlucky to get a sleuthing FD agent who would mess it up.

I make the booking in my name, add extra guests by name, then call or email to say I'll be arriving late can my companion check in ahead if me. Never a problem.

But usually it's my wife and son or daughter, which is easy to line up. You could say your girlfriend will be arriving early...