Hand sanitizer flammable?
If the alcohol content is high enough yes they can be flammable. Most however are not and use safer chemicals to sanitize.
The short answer is to get a high. Since teens are not able to buy alcoholic beverages in the US and hand sanitizer contains alcohol, some teens in Los Angeles tried their hand at using salt and directions found online to separate the alcohol and the sanitizer in hand sanitizer to get a high. It backfired when they landed in the hospital with alcohol poisoning.