"Morgan Stanley's Marriott code MOS is listed alongside Goldman Sachs and UBS codes in FlyerTalk's compilation of financial institution corporate codes. The SF Marriott and midtown Manhattan Marriotts were specifically cited in enforcement threads as properties that "cracked down on corporate code abuse." For financial sector codes, the discount threshold triggers audit flags — if Morgan Stanley's rate is 20%+ below BAR, full-service properties are more likely to verify. US domestic verification: 10-20% at urban full-service; Europe/Asia: meaningfully higher. No MOS-specific denial incident documented."

"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."

"I don't do mobile check-in if I'm wanting to upgrade. I check the app before I go in to see if any suites are available to book during the duration of my stay. If there is I just say "Would it be possible to get upgraded to an available suite with my platinum benefit?". Of course this is typically at the hotel that I stay in about once a month for 3 day at a time for work. The front desk pretty much knows me and know that I am fairly low maintenance."