First note: I dislike "zero tolerance" zealots.
Whether it's smoking, "drugs" (see: girl who was suspended from school over Midol), or pretty much anything else, zero tolerance is generally a stupid idea.
The primary thing, for me, is that they shouldn't be smoking near airplanes. While, in many cases, you can throw a lit cigarette into a pail holding gas with no effect (one of my friends used to do this as a demo) that doesn't make it right. I think the smoking areas, which are spread out nicely, should be used as intended. There is a ridiculously small chance, primarily with cheaper cigarettes, that the chemical the paper is soaked in will cause an ignition. That's just bad news and should be avoided. I fully support going up to smoker and politely asking them to extinguish the flame source near the potentially large source of fuel is wise. Should they refuse, then I think it's time to get staff involved, and maybe the guys (especially in the central square / warbird island / et al.) who own the planes involved to get the problem corrected. Do not be confrontational about it, because they're just going to be like anyone else who is being confronted. That means they'll go into one of two modes: flight or fight. Now they probably won't enter fisticuffs with anyone, but they will be as belligerent to you as you are to them. Belligerence is useless, and they may not really understand anyway until it is politely pointed out. Politeness usually wins, with a sheepish apology for the error.
The secondary thing, and this is because you want to harp on the dangers of smoking outdoors, is you're around Av-gas planes. According to the same people that declared smoking so harmful, Av-gas is a horrible (HORRIBLE) thing that contains unimaginably TOXIC lead. Now consider, for a second, that the amount of lead you're (in theory) being exposed to (especially if you touch or hang around the exhaust on planes, particularly Warbirds) is significantly more dangerous than smoke wafting by you. Do you think Jet A smells good? Most environmentalists don't. Do you think Av-gas has a great smell? Again, most environmentalists don't and they positively freak out over the trace amounts of lead. Tetra-ethyl lead has all sorts of nasty carcinogenic (and non-carcinogenic, but still unhealthy) effects on your body. Why, it's positively destructive to children! That's why there's such a push to find an alternative fuel. Do you want to know (because this is a huge airshow with a ton of Av-gas burning aircraft, in particular warbirds) how much lead is being shot out the exhaust? Trace amounts, of course (we use as little lead as possible) but enough to make an environmentalist's blood boil in rage.
This is the zealot's point of view:
"Should all of the good citizens of Oshkosh that live 'near' the airport be forced to endure the extra doses toxic lead from the fly-in / airshows? They should ban Av-gas (and Airventure, at least until a safer fuel alternative is found) IMMEDIATELY! Think of the CHILDREN! How many of them will suffer neurological effects from that lead!? How many people can actually afford to leave the area during the fly-in and avoid all that health destroying, tetra-ethyl lead!?"
That's what zero tolerance gets you, zero intelligence.
BTW: Ex-smoker, quit before I went to get my medical and it was PITA. I'm going on 8 years without a cigarette. I don't like smoking, but I dislike zero tolerance zealots even more.