"FlyerTalk community specifically notes the MMM code as "the go-to code for the Minneapolis/St. Paul area, described as extremely reliable at local Courtyard and Residence Inn properties, with a low risk rating." One user documented using an IBM rate for 14 years at 80-100+ nights annually and "never once being asked for an ID." Another stayed 500+ nights and was never asked. The 3M code is regionally well-known near 3M's Minnesota HQ."

"Bank One's Marriott code BOB may still exist in Marriott's GDS system following the 2004 acquisition by JPMorgan Chase. JPMorgan has a separate Marriott code (JPM). Legacy acquired-company codes are practically never verified as the hotel has no way to confirm employer identity for a company that no longer exists independently. Risk for legacy codes is negligible."

"I have never been asked (yet) at Marriott but usually I show up at the desk by handing over ID/credit card. Don't read this as me endorsing going crazy using the codes that you aren't supposed to use! Interesting about the client reports going back daily."