If you want a group of criminals to serve longer, than change the law, not say "Hahah you never get out!". Apart from that, the American term "Sex offender" can be anything from a 18 year old sleeping with his 17 year old girlfriend to a mass rapist.
There is a Urban myth of a guy who peed in the park and became a Sex offender because of that I dont know if this is true though.
That's not an urban myth, actually. Those convicted of public urination are eligible for classification as Level I sex offenders in some parts of the U.S.
Which is total insanity right there, as far as I'm concerned. And how "convenient" for the state's DOC (Department of Corrections) that they can get more warm bodies into their prisons on such mickey-mouse offenses, and make more money from them. Public urination should be made a low-MISDEMEANOR offense across the board, nothing more.
I agree, the contamination factor is a concern, for sanitary reasons. There are areas where there aren't nearly enough facilities built where one can get to a bathroom in time, like huge public parks where the nearest restroom could be over a mile away. As to public intercourse, I have to think a bit more on that issue. 