Kind of toeing a fine line between here and the Parenting Topic, but I can get why parents can end up too hands on with their kids. Not that I particularly have enjoyed having to deal with stuff like that in the past, but I can understand where they are coming from. There's a lot of unknown details that they don't know what could end up happening.
I mean there's definitely a fine balance that can be made between knowing when to put the foot down and when to trust the person - at the very least to let them make the mistake and learn from it (as annoying as it may be to see them end up doing it).
I speak only from personal observation, seeing friends of course end up in relationships but also one specific set of experiences with a friend of mine who's a girl and a bit younger than me and seeing her go through some relationships. I can only imagine how I'll feel when I have to deal with teenage kids.