I know someone that works in a hotel. They honestly don't care what you're doing. They sometimes have to do 12-14 rooms, each only 15-30 mns at a time. Gosh, my friend was just listing all the things she has to do! Lol. Sometimes they wonder about that. Leaving the door propped open is probably more of an indicator of what ya'll are doing than knocking. But it really isn't that much of an indicator. For all they know, you could have traveled with them, and somehow they placed your rooms apart from one another. You could have forgotten your card within the room. You could be visiting a friend from out of town. You could be in a secret love affair. The possibilities are almost endless.
My point is that they really don't know why you're there. All's they are hoping is that you don't take too many things off their cart, especially if they're low. If you say your pleases, thank you's, and whatnot, they'll be okay. Now, if it's a hotel that is out in the middle of nowhere, and they barely have guests, their minds will wonder. Usually those places are under-staffed.
Be relaxed! They don't know what they don't know. Meaning, they don't know why you're there. You're there for normal reasons until proven otherwise. Don't give them a reason to think otherwise! Lol. Be calm! Do some deep breathing before you go in. Concentrate on the latest baseball game, read off your to-do list in your mind, list off your favorite hobbies in your brain, or something that makes you think more logically (without emotion). Lists are great!
Also, if the music isn't on in a hotel, please help the lady turn it on. Some are either broken or too hard to figure out. You'll be more calm and relaxed with it on. I have forgotten a couple times to turn it on. I like peaceful silence, so sometimes I don't even realize the radio isn't on.
Private locations are very similar! The neighbors don't know why you're there. Be a normal person. Treat them like people you see at the grocery store, only very less chatty. Give them a casual nod, and be on your way. Don't make friends with the neighbors though. Be less friendly in a neighborhood situation, but don't be rude. She probably has an excuse for how many people visit her. You could always ask her privately. You could also bring a suitcase, or something similar.