Sometimes, how's that for an answer. Recently I vended at the Chicago musky show, I expected more in the upfront bait sales than what I did (I still covered cost and did well, just expected more) However on the back end I picked up a couple bait shops to carry my baits. I meet a lot of people, some very good connections. So while I had a ton of time invested and travel and all that jazz it made it worth it.
Sometime I do the small shows like $10 a table shows, I might sell 5 baits and make no connections. Its still fun, I talked to some people, hear a lot of fish stories, just enjoy the experience.
I guess if you enjoy what you do with your baits, its a good thing (provided your all legal with state tax codes and excise tax...) what is the worst that can happen? You lose a little money?