I board my animals at a private farm. I am the only boarder. I always ask permission beofre I bring any friends with to see my animals. If I can't come out, the BO takes care of them for me.
On the other side of it, is the barn where we do lessons. There are 4 different trainers there + probably about 100 horses that are boarded there. The BO probably has no idea whom half the people are that come & go out of there on any given day
Boarders of any animals (I board cows also) here know ahead of time that you do not send ANYONE, unaccompanied without prior notice onto my property. Everyone is very happy with this and if they are coming by after dark or in a different vehicle will send me a text prior.
If I were a boarder there's no way I would want a random stranger coming in off the streets to visit / feed / play with my horse. How is your BO supposed to know the difference between friend and stranger? Unless your friend has come to the barn with you a couple of times, signed a waiver, been made aware of the rules and shown the BO that they aren't "up to no good" then sorry, not their horse, not their property, they can't wander right in. I DO think the same standard is applied to family members, at least make the BO aware that your husband is your husband, your sister is your sister, etc. before sending them in your place. It's common courtesy at any barn.
Number one rule.. if its not your horse don't mess with it. If the owner gave written permission for the other person to come out, and if its alright with you and you need to accept the liability issues. I would state what hours any visitor would be allowed and that advance notice be given. If you choose to allow this.
I've always liked that rule Stevenson! Haha I don't mind if you pet it out in the field and check it out, but don't bring it up to the barn unless it's an emergency!
My BO has no problem with us bringing people out to visit the horses, but if they want to ride she has a waiver (that is available for us to pick up any time in the barn and have the person sign it). I trust her completely to look after my horses, so if I don't go out I know that they're taken care of, but we had a friend who lost her horses in a freak accident. All four of us: me, my mom, our friend, and the BO all knew each other and knew that while she usually came out with us, if she ever wanted to go and groom on our horses she was more than welcome. A situation like that I don't mind, nor find it invasive if all are in agreement. (I don't know if she ever contacted her before she came out though.) My BO lives on the property and quite frankly I hardly ever contact her to let her know that I'll be out. IMO she might live there, and I do respect that, but my horses are there as well and I'm paying to virtually rent on the back section of her property. I never go up to the house though unless I'm invited or I've contacted her ahead of time. And I respect her family time (so on holidays I might go out but I make sure to not ride in the 'arena' and instead ride in the horse field or just go out to visit).
Then again it's a small place with only a small amount of boarders, and we're all pretty low key. If someone strange does show up my boss will check and see what they're there for, but honestly the only people who've done that are ones looking for riding lessons, or asking about any horses for sale. :P Also, there's the fact that my mustangX gelding has a habit of running down people with bad intentions. We had two guys who decided to hop the fence (electrocuting themselves in the process), then go and 'ride' a horse in the field. We watched my gelding run them out of the field at a full gallop and every time they tried to get back in he'd run them out again. Poor guys ended up having to be rescued by us boarders and the BO because my gelding wouldn't let them leave a corner. He seems to know the difference between good and bad people because if someone who just started boarding and he's never seen before goes out there he might be alert and watch them, but won't do much more than come and sniff them and say hi. So that's our security! Lol
OP- are you the barn owner? If so, your barn, your rules. If you were uncomfortable with this person ( who you state you know... so not a stranger on the property) by all means talk to the boarder and ask them to let you know if someone has her OK to be there loving on the horse.
I board at a small barn... maybe 7 or 8 of us there. I think we would all give anyone we do not know, the 3rd degree...
We have to think about how the world has evolved over time; crime is a common occurrence. In fact, in September, a local equestrian center had someone tack up one of their best mares and ride it off the property without permission. It took a while to finally find the mare (it was unharmed) and the woman who had stolen it.
With this incident fresh in my mind, I can see how an unexpected arrival of a stranger can raise a red flag for both the boarders and the BO as they aren't aware of the person's intention(s). Before having anyone visit my horse and tend to its needs, I would make everyone aware of the situation and let them know who exactly is authorized to interact with it so that they don't 'freak out', thinking that someone is doing something that they aren't allowed. The last thing I want is to cause a scene.
I never take anyone to my boarding place without asking the permission of the owner. I think its just respectful. And I wouldn't want someone in with my horses without my knowledge or my being present. Horses can be unpredictable and you have to always be cautious of everyones safety. Likewise, she always lets me know if she will be in the field with my horses or if she needs to move them for some reason. :)