Barn Swallows nesting

I know someone who isn’t aware looking in a nest to see if there are Young in there is classed as disturbance last year they innocently wanted to show me some young fledgelings in a Robin nest before he comes back.when I saw Barn Swallows in the Barn I took a picture of one and after some time I noticed some nests.  I saw them going through holes in the ceiling and I saw a cupped nest made of Hay down the corridor and people do walk back and forth down this hallway cause they put there horses in the stables I told The person they are nesting in there which they weren’t aware of. And I told them I saw 2 Swallows go to the cupped nest at the end. I realised I shouldn’t of said that cause her response was do you think they have young in there should we just have a peep and see.that made me uneasy cause it would be classed as acidental disturbance. I told them I don’t think you should cause it will deter the parents from going near there nest and so they said shall we just leave it for now then. And I said yes. told her it’s red listed. She asked why and I said without going into detail I told her and she said that’s strange. While she probably won’t disturb them I know she is tempted to just have s little peep.and it’s in the stable she uses and the thing is I only go every now and again so most of the time when she goes I’m not I wouldn’t know weather she will try to take a sneaky peak. While I may not need advice now If anything does come up about the Barn Swallows or there is any advice would you mind trying to answer any questions I have if possible?