From actual experience... build a kid friendly, but not a family-style suburban RP and kids just don't come, under 200 traffic. Build a bog-standard dance beach and kids do come, to the point I can get over 10K traffic for events.
The few that do come to RP fully live in drama and fake-rumours and a desire to be officers and make all their own rules. A common fake-rumour being "Hey you know that xyz region, it's really a front for sex, don't go there".
I would so happily build a RP region fully for kids, but I know from bitter experience, it would be under 200 traffic after the first week as the kids all return to dancing and being boring. So, why bother?