Some folks are not comfortable picking up someone at the lobby ("walk of shame") or having him sign at the concierge. I've heard about escorts hosting in places that require that.
Again, a gay man hosting another gay men for sex (paid or not) is not rocket science.
If something like this makes you @Reisr30 concerned enough to post about it asking for instructions on how to do it without risking your life, don't do it or at least meet the guy first in his place before you bring him to yours.
Plenty of guys (professional or not) out there host, some even host while having roommates.