"I've only used corporate codes twice. Was never asked for anything at Hyatt Regency Waikiki, but was asked for proof of association at check-in at Park Hyatt Tokyo (which I did provide)."

"Costco's Hyatt code (66267) is a Costco member discount, not a Costco employee code. FlyerTalk discussion: "Costco Travel arranges negotiated rates for Costco members — this is a published membership rate, not a confidential corporate employee benefit." Costco members must show membership card at check-in, not an employee badge. The verification risk is minimal: Costco membership is easy to obtain and the card is easy to carry."

"I’ve never been asked at Hyatt but have at Marriott - specifically in Tel Aviv (which I was staying at as there were no Hyatts when I was there). You can also be working FOR a client whose company code you are using so it makes the idea of a company code and the verification rather meaningless."