"IBM (alt) Hilton code N2666284 is a secondary IBM code. IBM has multiple Hilton codes reflecting IBM's global corporate travel volume. The same FlyerTalk-documented enforcement pattern applies: "mostly never asked for ID" but with exceptions at gateway properties and a significant increase in European enforcement since 2022. IBM employee ID is a standard photo badge that Hilton staff recognize. The "alt" code likely targets specific IBM business units or international travel corridors."

"I would contact your corporate travel. I know some companies have one code for employee business travel and one for employees and their families. Some use just one for all. Shouldn't be too difficult to email to your travel team to get clarification."

"I run a Consultancy and work with clients across both Public and Private sectors. Many years ago (15?) a UK Government client (they are still an active client) shared a Hilton Corporate Code, which was to be used for stays required when working with them. This code gives access to (but not 'On Duty' rates). I use this code regularly across the UK (mainly London) without issue, staying most months at various London Hiltons."