Daily quoin limit is one of our newer game tweaks. It's been around for the last couple of test sessions. You can collect 100 quoins per game day, and some day it will be easier (possible) to tell how many you've collected.
I also like the Quoin limit, it adds additional game play = "should I collect this batch of Quoin or wait for a bigger payoff" and agree that the first time you hit the limit there is an opportunity to story-tell (hello Rock???) in a Glitch-type fashion.