While it's nice to fondle, test-drive, and "date" a flashlight at a gun show, I've found this approach to be less than satisfactory (for flashlights, not members of the opposite sex) because:
1-The prices are higher than the better online dealers (for flashlights, not *cough* members of the opposite sex).
2-Compare/contrast evaluation of various models is limited to "what's there" vis-a-vis the many/extensive reviews (see Selfbuilt's excellent reviews) available here at CPF (for those willing to do some patient research).
3-In general, I find gun show flashlight vendors tend to be less-knowledgeable (than CPF experts) and geared toward pushing stuff to Newbies/Joe Everyman/K-Mart shoppers.
4-After-sale customer service is poor, and "return" of a faulty product is difficult, at best, limited to tracking down that specific vendor at some future show (if at all -- good luck).
5-The show's bright ambient lighting totally prevents meaningful beam testing.
In my area, I do regularly see a knowledgeable Pelican dealer at shows. Recently, I've spotted multiple OLight and StreamLight vendors -- decent stuff, but all usually at max/retail prices. Also find a few Surefire sellers (doing it as a sideline) but somewhat negotiable re price.
The low-end 12-minute run-time import lights ($5-20) are spotted everywhere -- usually along with the sellers' calcified beef jerky, Beanie-Babies, Junk-Knives-For-Gang-Bangers, Usless-Fantasy-Knives-For-Ditz-Teens, Arrest-Me-ASAP Shuriken stuff, Fire-Breathing-Dragon-Barf/Chartreuse-Zolatone/Mall-Punk T-shirts, and used pantyhose.
YMMV.