This kind of stuff comes up every two or three years or so... popcorn will kill you... hot dogs will kill you. Municipal tap water, served at anything below room temperature will kill you (and even faster if it's fluoridated). Be sure to hold your pinkie out when you drink that nasty stuff!
I read most about major resistance to popcorn in movie theatres that serve "discerning patrons", frequently in upscale areas. Most of the time this comes up, it's an indie house... more rarely, a place that runs mainstream stuff.
Here's the other side of the scale. I have a 3-screen drive-in, located in a predominately military area with a sprinkling of high-tech. The place has always been well supported by its community, but much more so since the owners (us) actually paid attention to what the community would turn out for.
We cook our corn traditionally... Generous use of coconut oil, flavacol, "buttery topping" (not the junk stuff).
We have two full-sized poppers, one at each end of our counter. On the weekends, they're both going full tilt.
Only rarely does anyone ask how I make my corn, and I'll tell them exactly how its done if they ask. No real risk there... the popper has as much to do with how it turns out as the ingredients (which they can get locally, if they really want to). Coconut oil... yellow number 5, salt (Flavacol). In every case, our customer has asked for a large.
If you search for awhile, you can find at least one web site that will tell you anything you search about will kill you. Sure, popcorn is no different. The problem is more likely to do with the environment external to the product, because in most places, most people really like the stuff.
On airpopping: Yah... that's been tried. Back when somebody decided Canola oil was better, airpopping also cropped up as an alternative. Some theatres put dividers in their popcorn warmers, so different types could be offered. The airpopped stuff only remained "healthy" if you didn't turn around and pour topping over it. Nothing special about that... tasted pretty much like what you could make in smaller batches at home. Canola oil made concession areas smell like fish... so much so, that some theatres moved their popping operations away from the concessions & brought the corn to their warmers in large food bags. Only the most devout health nuts would buy it and even then, usually when they were being closedly observed by their health-nut friends.
Eventually, the mainstream theatres abandoned all that stuff, took out the dividers and went back to tradionally-prepared corn.
If you have a classy theatre, serving an audience with highly discriminating tastes, then you may have a challenge on your hands. However, if you keep your head to the ground, you'll learn what they like to snack on. Specialized goodies just might have to be a way of life for you.
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