the 88vip deal has been around forever and there's thousands of posts about it on the chinese "flyertalk" call FLYERT. You're technically only suppose to signup for this if you're a Chinese citizen and they've been really slack about this between 2020 and last year. However in 2022, there are data points of foreigners getting their Marriott account closed presumably they're able to easily track resident eligibility from your verified taobao account or verified Alipay (which requires +86 phone number or Chinese/HK/Taiwan ID number). Please be careful signing up for this if you're not eligible. I'm dual citizen and actually have two legal names so signed up for this twice since 2020.