I think the mods now make the whole batch of sign-ups visible after a certain amount of time has passed, so you can use sign-ups as prompts for treats. However, they do not make sign-ups visible before sign-ups have closed, which makes them useless for my primary purpose, which is to get a vague idea of all the likely assignments I could end up with based on my choice of offers. I don't like going in blind, and the letters are really helpful for that — and then for treats, as you say.