Go Ahead and Call her

Okay, so I'm working 11-7, we're full up, and so is everybody else in town. Almost immediately after I get in I get a call from one of our remaining reservations (she'll be GF, for girlfriend).
GF: Hi, I reserved a room for my boyfriend, and I just wanted to see if he'd checked in yet?
(Insert me going through all the rigamarole to check her identity and make sure that she is who she says she is blah blah)
Me: Sorry, but that room hasn't checked in yet.
GF: It's just that he's been driving a long way, and he's not answering my calls, and I'm a little worried.
Me: Well don't worry, our policy is that since the room's booked under your name, we'll have to call you when he checks in anyway.
GF: Oh awesome, thanks!
So several hours later, in comes a man looking to check in under that room--and he has a woman with him, and she is being VERY affectionate (he'll be AH, for Asshole)
AH: Hi, I'd like to check in? The room is under [GF]?
Me: Um, I'll need ID, a card for incidentals, and I'll need to call [GF] to make sure you're allowed in the room.
AH (with a very smug douchey grin): You go ahead and do that.
So like, this guy is gonna have sex with some lady in a room that his girlfriend paid for...and then he wants me to call her while literally, right across the desk, another woman is chewing on his ear???
Like, man, that's a level of douche that's way beyond my paygrade.
But then...then...both of the unfortunate couple plop down their IDs, and I see a way to use hotel policy to implicate the jerk.
Me (calling up GF): Hi, this is the [LordHelpMe Inn], I have a man by the name of [AH] checking in, can I have you confirm the reservation?
GF: Oh yes, thank you! [rattles off the numbers and info blah blah]
So I pick up the IDs and...
Me: And is [Other Woman] allowed in the room?
AH goes stock still, staring at me in disbelief. The woman is still all over him, none the wiser, and I hear GF take a deep breath.
GF: Sorry, what was that?
Me: He's checking in with a woman by the name of [Clueless Babe].
I felt super bad breaking GF's heart like this, but she deserved to know. And credit to her, she kept her cool.
GF: On second thought, neither of them is allowed in the room. At all. It's not too late for that, right?
Me: Absolutely not ma'am, but it is too late for a refund.
GF: That's fine, you can give it away to the next person that walks in, my treat--so long as you do not let him in there.
So I slide both IDs back across the counter, unable to keep myself from grinning like the cat that ate the canary.
Me: It looks like you're not allowed in the room after all. Sorry about that, have a nice night!