If you are that worried about getting caught, then

1.  you have not done proper research on the provider you are going to visit.  or
2.  this is not the hobby for you.  or
3.  if you are that worried, why are you doing it in the first place?

Just don't understand your mentality about it.  Relax and enjoy.  How can you really have a good time if you are so worried about getting caught?

Swim

I've never needed it, but I see no reason not to have it.

Even a well reviewed provider gets busted now and then and if you are on her dance card, you may need to call a lawyer.

What you ought to do is ask this question on the LA board.  I'm sure you'll get some PMs with names of some good criminal defenders.

I think you are a little to worried about this. When the time was that you had to stop your car to pick up a street walker, you never knew if a cop would pull you over after you did the pick up,and cite you with a traffic violation. however in the internet world of contact and appointments, especially in the big cities, no one gives a flying fuck about this activity. In most places vice does not bother sex workers if they keep a low profile and do not deal drugs or rip offs. Of course if you live in Mayberry, you may have a different take of the problem. All the more reason to find a well established worker and frequent one you can trust.