Eliot Spitzer, among other things, got busted for breaking the Mann Act, which prohibits "importing" a lady across state lines for the purpose of having sex.  I'm not sure if it's having sex for money ... the question is, does the Mann Act in any way affect touring ladies?  If I book an out of state lady before she's in the state, is that the same, even though she was planning to travel here anyway?  Any opinions?

You shoudl never use travelling girls because (a) it violates the Mann Act, and instead of a $50 misdeamenor, you could get a 20 year federal prison sentence and become a convicted felon; and (b) out of town/travelling girls are mostly a rip off.

The Mann Act, which is 18 U.S.C. 2422 reads as follows:

(a) Whoever knowingly persuades, induces, entices, or coerces any individual to travel in interstate or foreign commerce, or in any Territory or Possession of the United States, to engage in prostitution, or in any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title or imprisoned not more than 20 years, or both.

(b) Whoever, using the mail or any facility or means of interstate or foreign commerce, or within the special maritime and territorial jurisdiction of the United States knowingly persuades, induces, entices, or coerces any individual who has not attained the age of 18 years, to engage in prostitution or any sexual activity for which any person can be charged with a criminal offense, or attempts to do so, shall be fined under this title and imprisoned not less than 5 years and not more than 30 years.

The problem with statutory interpretation is that you know how the statute was read in the past based on the prior fact pattern, but that does not preclude a court for expanding the statute as new facts occur in new cases.  

When the Mann Act was passed, people were not posting on interstate forums (like the internet) booking providers.  The fact that no U.S. Attorney has ever prosecuted a customer for "touring ladies" who are coming to town anyway, would not preclude another U.S. Attorney from realizing the statute may cover that and try out the new theory.

A lot of time law developes as new facts allow for expansive views of statutes.

That said, going after the customer is less likely.  In fact, I would guess that only in this area is the customer ever targeted, and that is a reverse political correctness.  

I say this because in all other areas of "victimless crimes" the tendency is to go after the person higher on the crime scale.  Gamblers (the customer) will not be busted if the bookie (the seller) is available.  Users (the customer) is given a pass if he will turn over the dealer (seller).  Someone buying a pirated video tape (customer) will get a deal to rat out the person who pirated the tape (Seller).  

the same applies in the old days of bootleggers, today with smuggled cigarettes.  

Indeed, it is an anomly to go for the customer, even though saying so may be unpopular.

except when the customer is someone very high profile, like a governor or any kind of celebrity.

In the case of Ex Governor Spitzer, it serves the hypocritical asshole right. I do sympathize with most other high profile people who are treated harsher than the rest of us just because it makes headlines.

GaGambler is correct that the exception is when the target is someone high.  However, even there they are not "going after" the customer when it starts.  Rather, he falls into the investigation.  

Having caught a high official, it would look bad if they let him go.  As a result, they are likely to pursue it more than if he were just a regular customer.  The proof of this is that No. 9 is the only one busted so far, and I am sure they have a lot of other people using the services of that agency.

I once asked a city attorney friend why they were wasting public money on some of the stupid crimes like indecent exposure in a porn theater (that's how long ago it was. pre-internet).  He explained that they tend to bust bad guys and people "who are dumb in public." There are exceptions, of course, but if you flaunt it, they don't have much choice.