@Anonymous well thanks for the compliments. 😊
As a guest if i'm occupying a 3bedroom home with only 2 people, and paying a price based on 2 people, I know what they actually mean is "2 people per room" and this is hotel industry standard practice. I would feel rude and entitled to use more than one bed. Guests can clearly see that the price goes up with more people, correlating to bedroom use.
Whilst we grumble to ourselves, we don't say anything, or block off doors. However, in the 3rd room (with 2 single beds) we often leave them made up with just a bottom sheet, a folded down doona and cushions on the bed, which should look pretty clear that the bed isn't to be used. (a couple last week took the sb doona off the bed, I assume perhaps to snuggle with on the sofa in the lounge room, so I will have to buy a special blanket to leave in the lounge room to stop this from happening). Sometimes if we've been under the pump with turnovers we might even do the same thing with the second queen room, should we be 1000% sure that the couple who booked are sharing a room. (maybe only done this twice so far).
Reasons I don't like locking off rooms:
1. as you say, it's not good to "deny access", seems inhospitable
2. it's great advertising for return stays, a couple can see the other spaces and hopefully plan a return trip with family or friends. so having them all beautifully made up is just smart business IMHO.