"Shell's Marriott code SHL appears in FlyerTalk corporate code compilations. Shell is a global energy giant with major US presence in Houston TX. Marriott properties near Houston Energy Corridor routinely handle Shell employees. No specific verification-denial cases were found. The energy sector code pattern tends to be less targeted than tech company codes in current enforcement discussions."

"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."

"Deutsche Bahn's Marriott code 11353 is a German railway operator code in the global GDS system. Outside Germany, this code is essentially unknown to hotel front desk staff. German Marriott properties near Deutsche Bahn offices may be more familiar, but the code is rarely discussed in English-language travel forums. No verification incidents found. European public transit company codes attract minimal scrutiny."