In Dubai, Can the hotel seize your passport and documents for being unable to pay your bill fully? I have a friend currently in dubai and ran out of money and the hotel seized her passport and other documents. She has a money voucher but their bank said they can't cash it due to their economy and not being able to cash that much of a voucher. What is she able to do?
No. Not legally.
Passport retention is against the law in UAE. Your passport is usually the property of the government that issued it (as mentioned in the small print in your passport, which usually contains words to that effect), and each passport holder is responsible for its safekeeping.
(I'm aware that the source's page title refers to employers, but the quoted text states unequivocally that it is illegal to retain passports in the UAE.)