Kgirl apartment incalls. I have a routine I follow when hobbying that makes me feel safe and supplements my anonymity on the boards.
First, blend in with the locals. If its a mediocre building with not a lot of guys around wearing a suit, I don't wear a suit. I always keep a change of clothes in my car. Be aware of security cameras. I rarely park in an apartment garage because they all have security cameras. I always take a quick look in elevators to see if there is a camera. If so, I keep my head down and turn my back to the camera. Know your surroundings, and be aware of any lurking; guys standing around or in one place talking on cell phones. Military training helps with this awareness, so vets know what I'm talking about.
Don't loiter around the keypad at the front of the building checking your phone and waiting for the go-ahead. I prefer to stay in my car, parked discreetly at least a half a block down the street, until the booker tells me she's ready. Then I can go directly from car to the keypad and get myself inside quickly without having to wait outside, where there is usually a camera pointed at the entrance. I never allow my face to be fully photographed. I always turn sideways to the cameras.
In a complex with a few hundred apartments, there is bound to be people moving about, but its rare to see legit residents standing around. Keep moving. If you are standing around, you look suspicious. ALWAYS make eye contact and smile and say hello when you pass a resident in the hallway. Looking away or averting your eyes makes you look suspicious, so you draw unnecessary attention to yourself. If you look like you belong there in the building, you will not be memorable to anyone that notices you.
Probably the MOST important tip is NEVER be observed entering an incall. If there are other people about, I walk PAST the incall door and keep walking until the other people are out of site, and then I double back and go in. Sometimes this safety move takes five or six minutes, which comes off of my time, which explains why its the most overlooked by most hobbyists who seemed obsessed with getting their full 60 minutes regardless of the risks that are present. This is my standard safety protocol for every incall I go to, and so far, its served me well, and more importantly, given me complete peace of mind so I can enjoy myself without worrying who might have seen me go in or taken my photo.
Bookers I know have told me in the past that nosey neighbors are the number TWO reason they will have to move an incall. (Number one is an angry wife who gets ahold of her husband's hobby phone and sees the texts to the booker.) While men may be delighted at having the convenience of a Kgirl incall in the building where they live, wives are less enthusiastic about it, but fortunately, most young married couples in apartments in this price range both work, so they are not home during normal business hours. What raises the risk is doing something stupid to make yourself more noticeable. The number one offense is bringing flowers to an incall. People are more likely to remember you if you brought flowers to a particular apartment. Then later that day, a DIFFERENT guy brings flowers, and by the end of the week a dozen guys have entered the apartment bringing flowers. Residents are more likely to FOLLOW a guy bringing flowers to see WHICH apartment they are going to. If you take ANYTHING to an incall, put it in a plastic grocery store shopping bag with the name of the store on it. Then you just look like a friend bringing food.
So to answer your question, NO, the residents don't usually know what's going on until careless hobbyists do something to draw attention to themselves. In fact, you can actually use a prop to deter people from thinking anything suspicious. I know one monger who takes an empty briefcase with him just to look like an insurance salesman, and another who wears jeans, a T-shirt, and a tool belt with a hammer hanging on one side so that he looks like he is a repairman. Create an illusion that you are either a fellow resident or are supposed to be there for a legit reason, and you will help keep that location safe for yourself and others.