The generator provides its own protection, beit with a breaker or mechanical limiting. The temp cord must be sized to the generator and use an appropriate plug.
Also, I'm a bit confused when you say "independant"- do you mean this receptacle is not connected to the electrical system in the house, it's simply providing a pass-through so they can leave the generator outside yet plug stuff in, inside?
Oooh, that sounds fuzzy NEC-wise, as it would count as a 2nd service to the building which is a no-no. Also, the ground wire must be grounded. Honestly, though, if the cabling is sized to the outlet (20A cabling for a 15A or 20A duplex receptacle), I don't see a problem electrically/fire-wise. I don't like the idea of backfeeding a receptacle, though, as that would leave the generator cord with energized prongs and a potential shock hazard- the exterior outlet should either be a male socket, or a permanant connection. I see no issues with leaving it permanantly connected, though it's probably not advisable to leave a portable generator out in the weather like that.
If the HO is going to this trouble, why not do it right and give them a full-up transfer switch?
