Yes, you can get field safe ones. I bought one for my Shettie from Mole Valley Farmers (unfortunately it's too small, he's got a big muzzle!! ...eBay it must go!!)
Anyway, it has a velcro breakaway headpiece - which probably means the Shettie would get it off anyway, but still, at least if he wore it I could rest in the knowledge that he wouldn't hang himself!!