However, they're not significantly less-ordered than bank teller queues; They're hardly a "crowd" of independent actors following no rules beyond physics + goal

However, they're not significantly less-ordered than bank teller queues; They're hardly a "crowd" of independent actors following no rules beyond physics + goal that would necessitate treatment as a particle simulation. You're right if you wanted a really in-depth and granular model, but it's doubtful you'll find significantly improved insights versus treating it as a simple queue, and ignoring the fact that people are a little dynamic. As far as I've seen, most buffets constitute a line with a little bit of people skipping around. But it's very close to well-ordered.