Learn to use Hotwire with
www.betterbidding.com (or similar bid-reveal site). Look at the info provided on the hotel you're interested in, go to the city and neighborhood on the Hotwire hotel list on BetterBidding, and see if you can identify the hotel. If you can, with any certainty, call the hotel first and see if they have key carded elevators, and any other concerns you might have. They have no idea who you are, so you don't have to worry about exposing yourself and your intentions. If the answers are satisfactory to you, book your hotel and enjoy the savings.
Higher end hotels (in my experience) are much less nosey, with the very occasional exception. Don't make yourself a nuisance, and they couldn't care less that you're there. Low end hotels are different. For some reason, the people that work there seem to get a chip on their shoulder about their position of petty authority. They will be all up in your business. Avoid anything less than a 3.5 star if you can help it. They are used to hookers being a nuisance and causing trouble, so they DO care that you are there and will try to run you off if they discover you.
If you do get stuck in a hotel with key carded elevators, either ask for a room on a low floor, or tell him to go up the stairs to the second floor and meet you at the elevators there. Much more discreet. Even if housekeeping sees you, they don't care (especially at higher end hotels, low end hotels can be full of petty-power wielding douchbags) and have better things to do than worry about yet another possible hooker in the hotel. They see it ALL THE TIME.
Don't steal towels off the maid cart unless you're SURE she won't see you. It annoys them. Take a couple of dollars and go ask her for them. It'll put you on her good side. And if you're in the hotel for a few days, leave a fiver on the nightstand for her when she cleans your room, with a note asking for extra towels/washcloths. She'll take care of you. Most people don't tip them, so they love people who do.
Wear business attire checking in. Look tired. They will assume you are on a long business trip and possibly even take pity on you. DO NOT LOOK A HOT MESS. They see you, and they don't like you. Just look like you belong, please.
There you go. All my advice about booking hotels. Do with it as you please.