Well, this topic was first posted in 2008, and who knows what was changed in laws!
I think, laws are changing so fast in Latvia that you can't follow them in time.
But most possibly, this law works by now. If you would check a "sex service" boards, most likely girls are only inviting to themselves, and do not offer boarding on external territory.
Well, I think prostitution means you have sex and give money for that.
It's not like boyfriend-girlfriend situation at all. I guess, no prostitutes will accept your movie tickets or petrol instead of sex, ha-ha