On the subject of this not being appropriate for a kid's game: I disagree. We involve heterosexual romance in kids media alllllll the time; changing the genders of the people involved doesn't suddenly make it inappropriate for kids.
I still totally think OP's suggestions are unnecessary for Runescape; I just have to disagree with that particular line of reasoning against it.
I think I meant to come across more as it's not appropriate to ask them in game whether they'd like to marry the prince or princess directly for example, not that exposing them to it was inappropriate. Like people shouldn't be forced to give that kind of information to continue a quest whatever their age