So, flying back into Dublin airport last night, the entire Lufthansa flight emptied into the T1 passport check area to be 'processed' by one lone Garda. I was at the back of the queue, and was waiting about 30 minutes.
Some people, no doubt, were non-EU and had visas to be stamped. These visas have time limits - but because no-one checks anything when you leave the country, there is nothing to prevent overstaying. You can overstay and leave when you feel like it. There is no enforcement so there is nothing preventing an overstayer from reapplying for another visa. If you overstay by 4 years, go home for a week and then reapply - the embassy has no idea that you overstayed - they just see that you got a visa 4 years ago. They give you another one.
What is the point of such a system? Why check at all?