Yes, I have. My horse had a huge sarcoid on his ear removed by laser surgery, so I used these to keep flies away from his surgery site. I attached a bit of cotton to the tag and plaited it into his Kane just behind his ear. It worked well.
I found a photo, I started off by using string but then moved on to cotton and doing it abit tidier looking. At the start if using them they kept falling out and I would end up walking around the field looking for it lol