"Pfizer holds two Marriott corporate codes (4899 and PFZ), reflecting the company's size and travel volume. FlyerTalk's Marriott ID thread notes: "In the US and Canada, never asked to show a work badge. Overseas — they tend to follow the rule by the book." One key risk factor: Pfizer's dual-code structure suggests a formally managed travel program. Corporate contracts sometimes include provision for hotels to share guest lists with the company — unauthorized users could be flagged to Pfizer's travel desk."

"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."

"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."