Depends on how they work.  If the verification service knows that Agency (or Provider) X called for verification of Client Z at such-and-such date and time, they might keep a record of that.  If Agency X can provide enough justification, then the verification service might give you up -- if you beat up the girl, for example.  That won't help them so much if you only used the verifier the first time, and were then regarded as "trusted client", but it's still a place to start.

Be clear about what you're worried about, and about the risks you might be running.  You also want to recognize the risks that the girls are running as well.  It is not enough to think, "Well, they can't make a charge stick", because you might have other things at risk.  What if LE runs your plates when they see your car parked outside a suspicious location, and sends a letter to your wife to advise her that the car was spotted?  What if they call your employer and ask if your whereabouts can be verified for a specific time (which might be when you were at a "client meeting")?

You want to avoid coming to their attention at all if there is anything that you have to lose.  You could probably sue if LE tried some of the tactics listed above, but that won't get you un-fired or un-divorced.  Even if you did sue, you'll wind up in front of a judge who isn't stupid, and will be looking at whatever proof LE can bring to bear.  He'll want to rule against you if it's obvious that you're just trying to beat the rap, and he might find a way unless you and your lawyer are slick AND lucky.

In general, if you have a lot to lose, have a low tolerance for risk.  You can't have a ZERO tolerance and still be involved with the hobby, but you can be extremely careful.  Things still might blow up on you (see "Eliot Spitzer" for an example), but you can decrease the probability.