I've thought about this myself but realized it wouldn't really work in the long run. I can see some players leaving less than appropriate messages in it.

I think it would also become a data storage issue for SE. If they were inclined to add it, would they limit it to the 20 most recent messages? Would they allow you to flag messages you wanted to keep so they don't auto-delete when the message limit is reached?

It's just problematic.