Kinda hard to separate actual now-writers from then-writers, though. Best I can think of is watching the upload times of chapters to see if they're too quick. Problem is the latter can just schedule their uploads beforehand so they can mingle in with the former group.
I like to think that I'm a reasonable guy, and I get mad in situations where the majority of others would too if they were in my place. Problem is I can never seem to hold onto a grudge when I get showered in gifts.
I'll admit the idea came to me once while scrolling through RR as well. "What's stopping people from just stockpiling a story until a writeathlon comes along?" Nothing, really.
I always thought it kinda defeated the purpose of one.