We brought a poorly sheep into the barn a few weeks ago and gave her a hay net. I thought she would be ok as she didn't have horns.
However, when I went to check on her before bedtime, she had caught her button eartag on the netting. Thankfully she was quite a dosile old girl, so just stood still rather than panicking and tearing her ear. However, I've now given our haynet away to a horsey friend, and will only use fixed racks for our sheep from now on.