Basically as hobbyist we have no way of knowing what providers do with their significant Others, or their clients.

Just as providers have no idea what we do in our private life.

So your question is unanswerable, because of the fact of not knowing what activities providers provide on and off the clock.  

You might read in a review that a provider only offers "cbj" however she could be performing bbbj/Cim on her Husband/Boyfriend.

While I'm sure it does matter if a provider cleans up between sessions, I don't think if you DATO her you can be totally sure you won't pick something up.  And this would be true of anyone.  In may case, I got a case of gastro-enteritis, though I'll never be sure if I got it from DATO with a lady.  I think it can happen even if she seems "squeaky clean."  Fact is, there are lots of ways to catch things in this hobby.