"HSBC's HSB code is listed across all major aggregators and rated "Sometimes" by hotelcorporatecodes.com. HSBC has a formal Marriott Bonvoy partnership (HSBC Premier cardholders receive complimentary Silver Elite status), making the brand relationship well-known to hotel staff — but this awareness cuts both ways. Finance-sector Medium calibration applies, with higher risk at NYC Midtown and London properties where HSBC has dense employee concentration."

"I have been asked to show some proof couple of times. I normally show my corp id but credit card with employers name on it has worked, too. As would probably just showing my laptop with employer e-mail account or whatever. My impression has been they are happy with just about anything that proves I'm working for the company whose rate I use and why wouldn't they."

"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."