I wouldn't listen to anyone telling you that you are smothering..you did just the right thing...I wonder if it had been their grandchild wanting to go alone, to an isolated, dark, wooded recreation ground, on a stormy night, where they knew nobody, and quite possibly wouldn't have a phone signal, if they would be comfortable with that..knowing the parents would hold them responsible if anything happened to their daughter... I don't think so somehow... so I wouldn't feel guilty at all.. and if your grandaughter couldn't see the reasoning behind why you were worried I'm afraid she probably isn't quite grown up enough to deal with the unexpected just yet..the only extra thing I would say is, maybe, as some suggested, tell her next time, if she really wants to go that she has to ring her mother for advice first.. and maybe set out a few ground rules with her parents to begin with.. when my boys were young they knew that whichever grandparent was looking after them was the one who set the rules and they should respect that. I do remember being 17 and thinking I knew everything too..it's only with hindsight that you realise you really don't.. I'm sure your grandaughter loves you and really knows you are looking after her safety, so don't worry...it sounds to me like you do a great job.. better than all those families who don't give a damn what their children are up to!