If an agency is busted and they find your address in an address book or on the computer, HOW can anyone PROVE that anything illegal occurred just by seeing someone's name?  Can any of you legal eagles answer that one?

You're right.  They can't prove you committed a crime just based on finding your name in an address book.  But they CAN use that discovery as the starting point of an investigation.  Depending on what else they come up with, they could make a case against you, or set you up for a sting.  The odds are really against this sort of thing, but it could happen, especially if you already have a record and are still on probation.

The problem is not so much that they may bust you. The problem is with the fact that your name is on the list in the first place.

What LE usually does is threaten to release the fact that your name is in the book. The person usually becomes concerned for fear of public retribution more than the hobby related crime (usually a ticket).

This is the tactic LE uses to garner cooperation by named clients.

The hobby is a misdemeanor violation for the client, and as such must be committed (usually)in the presence of LE. Every state has different laws. But for the most part, we must be caught in the act.

If LE finds my name in an address book, they can approach me about it... but (1) I'm not obligated to answer any of their questions, (2) if they publish ANYthing about my name being in the address book - to anyone, including my spouse - without at least arresting me on a related charge, I have legal recourse against them, and (3) they can't arrest me for anything.

The cops love to use this sort of intimidation to get you to voluntarily give them info they can then use against you and/or others.  Don't fall for it.

Not really true.  In Minn. cops can post your name without arresting you, if it is part of the investigation.  They can go to your place of work, home, church, whatever to question you.  They can also get warrants to search records, such as credit card transactions to see if the amounts spent at the location are in line with the costs of doing business.  Yes, you can remain silent, but that does not mean the damage by LE wont dont some serious harm to you or your family.  Also, if your name is on a client list, and that info is found after a SW, that info is public info and can be found by any reporter to publish,,,and I wouldnt put it past LE to use this tool to put pressure on you.  I would avoid telling these people nothing can happen and Ill just sue scenario,,,,,you will get them into something they might not have to get into.  Just tell them you went there, did or did not like it,,and move on.  Nothing they can do after the fact, but dont piss them off either.  Just make sure who you see does not keep those kinds of records,,,,not good business.  Why would they keep records anyways,,,,not like they are paying taxes on the income.

the agencies will get your personal info and agencies keep detailed records because they are "legitimate" businesses.  that is why i tend to see independents and ask about how the personal info is handled.  i always ask the provider to destroy my info within 24 hours of our first engagement, except for my phone number of course.  i make a point to remind her at the end of the engagement about our agreement.

. . . you probably WON'T have legal recourse against the police if they reveal what they learn about you.  

For one thing, individual police officers, their departments and the cities they serve are generally immune from such suits.  Even if they aren't immune, you can't win a defamation case against anyone if what they say about you is true.  Your only other potential recourse would be for invasion of privacy, but if they legitimately find the records on someone else's premises they have not invaded your privacy in any way the law would recognize.  Even if they violate the provider's privacy rights when they obtain the records, you would have no legal basis to complain about violations of the rights of a third party.  

The law would be sympathetic to someone arguing that their bank records should be kept confidential because the law encourages confidentiality in that setting, but the same argument applied to a provider's records would fail because the law does not recognize any good reason to protect this type of information.  The law wants to encourage people to do business with banks by helping protect the privacy of their records, but it wants to DIScourage people from doing business with providers.  Protecting the privacy of this type of record would actually be contrary to public policy.

I agree that prostitution shouldn't be a crime, but it is.  No one has a legitimate legal interest in being able to get away with a crime.  If the police find a buyer's name in the records of a drug dealer, should they be afraid to use that information because the buyer might sue?  Of course not.  The same logic applies here.