A week ago a friend of mine came here with her DC's girls aged 8 and 10 and a baby. 8 yo grabbed my guitar - twiddled the tuning keys, tried to play it like a bass and generally manhandled it. They both generally wanted to mess with DS's electric guitar and his keyboard and most of the other instruments like recorder, harmonica, were left in a saliva encrusted mess at the end of the visit.
Generally they went around downstairs and in DS room touching everything, stuff that was well out of their reach - even things on top of the wardrobe FFS! Also kneeling/sitting on arms of sofa - that kind of thing. Some things did get damaged.
This is not the first time something like this has happened with other DC's and actually was not the worst it has been. We are very easy going here and I just bite my tongue, but that seems to give them carte blanche to go around grabbing everything! Should I be a bit more strict?
Usually these are not friends of DS but are DC's of people who we know. WOuld if be wrong of me to just ban DC's from DS room unless they are his own close friends, and to have some basic "house rules" generally?