I am a licensed trapper and have only recently begun experimenting with snares.
Just because it is legal to trap in an area, doesn't make it a good place to trap.
One really needs to excecise some good judgement in snare palcement as far as proximity to people and likelihood of snaring domestic animals.
I have been travelling 4-5 miles into the woods and into places rarely frequented by people or pets to set my snares.
Bob,
I am far from an expert but from the picture it looks like the guy made no attempt to hide his set and it looks like a pretty wide path to set without some attempt at funnelling. His snare is dyed and appears to be well anchored to the tree.
If you have a chance to visit it again, check the snare for a tag. If there is no tag it could be someone dabbling illegally with snaring.
Trappers have a choice to have their name on the tag or just a number that is registered with Fish and Wildlife. Most guys, as did I, opt for the plain number.
If the snare is in an obviously dangerous location with regard to risk to the public or pets, you could call F&W and have them contact the trapper about the set.
Scott