There's now this Note in the Cathay travel restrictions for Hong Kong:
"Note: Hotels will not be eligible for home quarantine. Anyone who does not have a home address will be refused entry."
Not sure if this only applies to some countries. Indeed, not certain it's correct, since I haven't seen it elsewhere, but the rules
are constantly changing. Nonetheless, it strongly suggests that at least if you're flying Cathay you may have trouble boarding your flight without a HK home address.
https://www.cathaypacific.com/cx/en_...trictions.html