I would only be open to an incall situation at the providers apartment, and wonder how they
keep the neighbors from figuring out what is going on?

I assume it would be easier for LE to set up
a sting there too.

Any thoughts?

For a provider, doing incalls at their residence is perhaps the most risky and costly mistake they could make.

Aside from the obvious initial LE charge, they set themselves up to forfeit all personal belongings in the residence, lose the residence if they are purchasing it, or be kicked out immediately if renting, child endangerment if they have kids who live there, and more...

can go wrong.  LE is a big concern but a stalker or true psycho could be a big danger.