I board horses here, I am out daily and usually notice anything that might be hazardous but sometimes a person can miss something. Talk to the BO nicely and tell them about the things that you feel are unsafe......
Two years ago one of our boarders horse kept hopping into the round bale feeder, I took him out of that so many times! Then one morning I went down and he had degloved his hind leg, it was in the winter and it looked like his foot had slipped under the metal bar while he was trying to jump out. He was 3 at the time, now two years later.....we didn't use the round bale feeder last winter, I hauled the hay out twice a day for the horses because I was afraid he would climb in it again! Last week I came home in the evening and decided to go down to check the horses and guess who is standing in the feeder! I tried to lead him out but he wouldn't budge! I guess he remembered the last time he hopped out, so I had to get my hubby down to flip the feeder over top of us so I could get the horse out LOL good thing he's a real quiet boy! We took the feeder up to hubby's shop and added 1 foot legs on it, now he won't be able to do that!
We have trees/bush in our pasture which the horses stand in to get out of the wind/rain/snow.........they could easily hurt theirselves on a broken branch playing around in there.......there are some things that just can't be full proof.
Thank goodness the owner of the horse that injured his leg didn't blame us or sue us! Trust me I'm sure your BO does not want any injuries anymore than you do......talk to them and voice your concerns.