It'd be pretty hard to hit a pet with a scythe used correctly, as you have full control of the blade at all times and it's pretty easy to stop/divert if necessary. I'd rank it about as dangerous as a push mower, which could catch a tail I guess.

My dad got one years ago from https://scythesupply.com and it works great, especially with the longer/taller weeds. Looks like they only have left-handed ones in stock "right" now.