"DLA (Delta Air Lines) is listed at hotelcorporatecodes.com with verification "⚠️ Sometimes" and 10-15% discount, North America scope. No dedicated FlyerTalk thread on Delta/DLA ID enforcement was found. General pattern for airline employee codes at Marriott: medium risk, primarily because airline employee IDs are easy to request (physical company badge) and airline employees are frequent Marriott guests, making front desk staff more practiced at requesting verification. Properties near major Delta hubs (ATL, JFK, LAX, MSP, DTW) have higher awareness. Select-service and suburban properties: rarely checked. Full-service urban flagship properties: occasional."
— hotelcorporatecodes.com verification database; AeroPenguin Marriott code list
"I occasionally try to get the corporate rate for a company I'm visiting in the area (for sales/consulting). Only once has a front desk clerk asked me to prove my eligibility, and she was satisfied by me giving the name and telephone number of the person I was visiting."
— FlyerTalk_User
"I get asked every single time on Government Rates/Per Diem Rates. (Multiple properties per month) I just know to keep my ID right there. Every once in a while they will try to photo copy it and then have to explain that isn’t allowed, otherwise I have no issues with it being validated."
— chrismholmes