aerosol propellant in product residue?

Factual Questions
1

Does the propellant in a spray can (often highly flammable propane or butane) really get mixed in with the product it’s dispensing, in such a way that whatever you’re spraying also becomes much more flammable?

This is inspired by the mythbusters episode about tasing somebody who’s been pepper sprayed causes their clothing (a flannel shirt) to ignite and burn vigorously.

2

Gaseous propellants tend to evaporate within seconds, if not almost instantly, and most are inert. What might be flammable here is an alcohol or similar base for the capsaicin oil that persists long enough to be ignited.