If the lady is going to leave the door open, she should say that to the client right when she's telling him her room number:
"I'm in room 632. Please don't knock but just come on inside."
There have been many ladies who have left their doors open or even slightly ajar. There have also been many ladies who have left the door locked, presumably so that they can look through the peephole to make sure there's just one non-LEO guy standing outside, not 2 or 3 guys. Personally, if I were a provider (besides the fact that I'd always give myself freebies!), I would keep the door locked. Not just for safety, but also for discretion. If I'm a maid and I see a guy walking down the hallway reading off the room numbers, I might, sure, think he's coming to see a friend, but I might as likely think he's coming to see a provider. The maids aren't stupid, you know.
Let's put it this way: If I'm the one who's renting a hotel room and a friend is coming to visit me, here's the way it usually plays out:
"Hey, Joe. My room number is 632."
"Okay," says Joe. "I'll see you soon, around 3:00 p.m."
Do I leave the door open for Joe when I'm waiting for him to show up??? What if he's a half-hour late? Do I leave the door open from 3:00 p.m. until whenever? . . . Of course not! The hotel room isn't that big, after all. When Joe shows up and knocks, that's when I'll unlock the door, ESPECIALLY if I'm a lady.
IMHO, if I'm a provider using a hotel room to conduct my business, I'll ask my clients to call me from the parking lot and then I'll unlock the door a few moments later, since I know they're on their way up.
MOST hotel guests who give out their room numbers to friends and business associates don't necessarily expect their friends or business associates to call again from the parking lot, right? They expect their visitors to just show up and knock on the door.
IMHO, it's providers who are more likely to leave their doors unlocked, NOT regular hotel guests.
If it's my house in a nice suburb and I expect my friend to show up at 3:00 p.m., I might - just might - leave the front door unlocked starting at 3:00 p.m. Or I might expect to hear my friend come up the driveway, and then I'd go unlock the door. Or I might just figure that my friend can go ahead and ring the doorbell when he arrives, and then I'll open the door.
But when I'm a lady renting a hotel room . . . Am I going to keep my door unlocked when any ol' guest could just push open an unlocked door and maybe assault me? Maybe if I've got my chain on or some other way to make sure that a creepy stranger at the hotel can't just open my door and . . .
IMHO, it's INDISCREET to leave the door open.