My guess is that this law would be struck down by any reasonable judge. But the problem is that to challenge a law takes a shit load of time and resources, and I'm pretty sure that not too many well-to-do folks with nothing better to do than fight tyranny have been arrested under this law. If the ACLU really wanted to get involved they could have someone get arrested intentionally (a la Scopes Monkey Trial) to attempt a challenge. Not sure anyone would be willing to take the risk of having an "attempted prostitution" conviction on record.
Right on point. I was about to mention that the problem is that the system is working backwards. Innocent until proven guilty? Absolutely! But why don't you come downtown with us for a couple nights or until you make bail....