Barns and coops attract all kinds of interested visitors. Our worst experience was catching a neighbour's kid trying to bridle and ride our greenbroke mare. Fortunately we got home in time to prevent an accident- that mare was great with my husband but not anyone else. Her parents were suitably embarassed, it never happened again.
Most visitors are kids or parents who want their kids to experience farm life without the inconvenience of manure. Our horses were on local television without our permission, too. You have to roll with it, understanding that most people are fascinated by what we do, even though they wouldn't or couldn't.
I allow a certain duo, sisters, to groom the old horse because they adore him and he has mutual feelings for them, and because I know they watch over the farm for me, without having to be asked. Two other sisters are not so great, the younger is capable of trespassing and luckily older sis watches for that.
It's a part of rural life and though I do not want to lock the barn it might happen, because a case of rustling occurred here recently- two cattle taken from a barn and slaughtered in their field while the owner was home. Gulp.