After reading the delightful 'is it okay to eat on mass transit thread' I couldn't help but think--context is everything. Regardless of one's personal opinion, the consensus seemed to be that a bagel didn't draw second glances, but tucking into the Number 3 combo meal with pork fried rice, French Fries, or garlic bread for your side was worth a second glance.
Other than mass transit, what is the weirdest out-of-context eating you've ever seen. I mean, not that the food or the occasion was 'rude' so much but the juxtaposition of the two.
For example, in most college seminar classes I've taken, it's okay to have coffee and an unobtrusive snack like a pastry or protein bar, especially during and after the break. Actually, it's a necessity for many students, given their schedule.
But--years ago, yet it still sticks in my mind--I recall going to a 'funding your grad school' seminar and a woman brought an ENTIRE large container of Stoneyfield yogurt, very popular then, and proceeded to eat from the container with a metal spoon (clearly she'd brought it from home, she hadn't just been to the grocery store) and occasionally pouring granola from a box in her backpack onto said yogurt.
She finished almost the entire huge (largest one they make) container during the session, and only stopped because it came to an end. It seemed like such a strange, asocial act of eating in public, like something you'd be more apt to do late at night in fuzzy bedroom slippers than at an informational session. It wasn't rude--it was in an auditorium and not distracting, but just odd. Just an odd pairing of amount and type of food with context.