Corrected
See K.S.A. 21-3504.
When a 19-year old bangs his hs sophmore girlfriend who is still 15 going on 16, that's aggravated indecent liberties with a child. When this happens, the girl's parents are usually pissed (not about the age of the dude, but because their daughter's doing guys period). The local prosecutor has to do something to appease the parents, but doesn't think a 19-year old doing his girlfriend who may only be 2-3 school years apart warrants prison. A deal is reached where the dude will plead guilty to the technical crime, but all parties agree that the usual mandatory prison won't be imposed. The rub is that the guy has to register as a sex offender, with no way to distinguish typical hs activity from what's usually thought of sex offenders.
The same statute could also apply to 40-year old dudes who troll roller skating rinks for 12-15 year-olds and do stuff to them. Those people go to prison, but are still guilty of and registered as the same offender that Hughes is.
I'm guessing the first scenario here is what happened to Hughes.
With appeals to the criminal case as well as to the administrative aspects of the registration, it wouldn't be odd for this to have happened in high school but just getting registered now.
If the dude is 18 or less and less than 4 years older than the girl, it's "only" unlawful voluntary sexual relations per K.S.A. 21-3522.
