Occasionally I see providers advertising incalls late into the evening. I am reluctant to see providers
Late at night because I feel that this must attract a lot of unwanted attention from hotel staff.  
Am I being to paranoid about this.

Hotel staff are use to providers being in and out. The general rule is that the cheaper the hotel room, the more they care about ecorts visiting clients (because classism). The more expensive your room, the less they care about who your vistors are.

...you're being too paranoid.
Imo if anything even staff seems more relaxed.
I offer incall to start up until as late as 11pm (sometimes) midnight.
I'm careful in the hotel (or residential incall) I pick as well. I wouldn't work out of anywhere I didn't feel comfortable at in anytime of the day (or night).

But in this situation, you can probably relax. Usually the evening staff is too busy with paperwork or playing candy crush to even warrant a head nod lol. Just remember to ask your chosen lady of the night to direct you to her room (if she doesn't offer). Knowing where the elevators are and not fumbling with your phone in the lobby should help ease a bit of your anxiety. If that doesn't help, try thinking about boobs. Ass. Or kittens in winter coats. 😏