Q: What do you do when another guest with a key card comes into your hotel room? It happened to us at one of the ritziest resorts in Las Vegas. Check-out time was 11 am, but we called and received an OK to stay until 12 noon.

A desk clerk didn’t get the message, issued a key and sent a couple up at a little after 11. We’re still mad, but is there anything we can do about it not happening again?

A: The simplest solution is that whenever you’re in the room, keep the deadbolt latched. If the key card opens the lock, the door would still be blocked. Another suggestion if your room is invaded is to make a big fuss.

Wanna do something snarky? Business travelers we know who experience that all-too-frequent embarrassment or other example of bad hotel service, always do a dramatic anger performance that would make Greta Garbo jealous. Result: They get a free stay next time, and are usually upgraded to a suite.