Well, since the client is paying my expenses & does have a discounted rate at the hotel, I'm assuming they told me to use their corp code for 2 reasons: 1) it helps them fulfill their room # obligations to ensure that rate; 2) it means their expense check to me will be less. Why pay extra if they don't need to?

If the hotel does actually ask for id, I'll explain that I'm there on behalf of client & client told me to use their code. If there's a problem I'll pay the rack rate (rather than try to find another hotel at 11:30pm) & let the client sort it out w/ the hotel directly the next morning.

Cheers. Sharon