"HP (alt) Marriott code 5105 is a secondary HP/HPE code, alongside the primary HPQ code and alt code 5444. HP's primary Marriott code HPQ is one of the most widely shared codes in FlyerTalk's publicly usable Marriott codes thread. The same risk profile applies to alt codes: Marriott's automated system has been documented to disable Mobile Key for high-risk codes, forcing front desk interaction. HP-heavy markets (Palo Alto, Houston TX) have heightened verification. No 5105-specific denial documented."

"I wouldn’t mind that at all. Credit Card companies have super weak security and it’s very easy to defraud them - they just pay our money back, and counts that as losses so we’ll sure up about it and keep using the cards What I mind is that the mobile check-in is basically a lie. Marriott is deceiving me. Random hypothetical people that might or might not stole my credit card are not. Hilton works just fine btw"

"I now always make it a matter of course to carry documents (business cards of my contacts, e-mails requesting my visit etc.) from my host company when I travel. This has always proven sufficient for the few times I've been challenged by the front desk clerk."