No, snares are not weapons.
I wouldn't appeal to shields, either. They aren't weapons, if we're classifying things, though they can have weapons attached to them (boss, spike) or be used to make an attack (bash).
A specific ability that affects any weapon you wield may still affect things that aren't normally weapons, when you wield them as improvised weapons, but that wouldn't help a snare either, since you don't wield a snare.
If you have an ability that say, gives all your weapons ghost touch, does it apply to snares?
Consider that shields are the subchapter right before snares, and any argument for one is equally valid for the other.
Snares can be improvised weapons if you smack someone with it. Unless you are physically holding the snare I can't see how it's affecting them.
As to a shield... It's not a weapon but is a martial weapon for proficiency... For Ghost Hunter, I'd say it's enough of a weapon to be affected by it [you are wielding it to hit someone with it].
Unless you are physically holding the snare I can't see how it's affecting them.Can you actually hold a snare? I thought that snares can only be built on the spot you are setting them and before that you just have materials
Some feats allow to to prepare a snare for quick deployment. Nothing stops you from smacking someone with it before deployment as an improvised weapon: it of course can't be used as a snare until deployed.