They do?

You must be a economics professional working for the goverment.

Pre booked online upscale inner city hotel room 200/night. Pre booked airline ticket RT, from anywhere in the country to anywhere in the country $200/$300.

Four night stay in a major city - $800 Hotel room plus $300 for airfare $100 for cab - porn stars don't use free shuttle buses, do they? Meals $50x4 = $200. Grand total $1,400 for four nights.

Income, we'll figure a extremly conservative scehdule figuring that she might want to limit herself to four clients a day. We'll exclude multi hour dates and go with simple one hours. Four dates a day, four days, 16 dates altogether.
16 x $500 "normal fee" $8,000 plus 16 x $500 for "expenses" $8,000. For a total of $16,000.

 Let's see, $8,000 for $1,400 in expenses. Hmm,you do work for the goverment, don't you?

 So, by completing this simple logic puzzle we come to two conclusions. The economics reasons given, as I stated before do not add up. And second, is it too late for me to become a porn star?