There are plenty of other things that the kid could be encouraged to do after school that might be more aligned with his or her desires and talents. Chess club, Students Against Drunk Driving, Yearbook, Debate, whatever. Heck, back when I was in school, my mom had me do the Latch Key kids program (a place to sit and study for kids whose parents wouldn’t be home from work until several hours after school ends) so she could do whatever she did at home alone all day.
I also agree, however, that even though you may not want to picture your parents getting busy in the shower, it is important for them to have alone time, too. The kid might be their entire world, but if they don’t take time for each other, bad things can happen.