The more I think about this new law, the more I realize how hard it is going to be to police. It's hardly going to make any difference, it's not as if the Guards have the resources to engage in sting operations anyway.
Also, lets face it - the country is bankrupt, completely and totally. The Irish taxpayer can't afford for the Guards to put too much resources into it, there are far more worthwhile crimes for them to be giving time to. The better thing would be legalizing prostitution not only morally but financially too, it's worth nearly €6bn to the German government as it stands now for instance.
Related, I notice this site has sister sites in both Sweden and Norway where a similar law has been around for quite some time. Not as many girls on those sites mind you, but it seems punting is alive and well there too.
http://www.escort-norway.com/
http://www.escort-sweden.com/