The wasp spray sounded like a red herring, and it is.

http://www.snopes.com/crime/prevent/waspspray.asp

Some things to consider: Pepper spray is a defensive weapon, and can be classified as nothing else. It's legal, vetted, and reliable.

Wasp Spray is a chemical spray formulated to interfere with the nervous systems of insects. Guess what? What it does for one species, it will do for other species. Basically it's nerve agent for bugs.

The range makes it into something a decent attorney could play hell with, it's not defensive, it's offensive.

The chemical makeup would be another thing you'd be liable for.

Don't play footsy, if you have serious concerns about this individual, get training, get a permit, get a gun, and practice with it. If you're not going to train with the weapon to become proficient, don't bother, though. Stick with the pepper spray.