I hate to be annoying, but I'm going to bump this topic as I've continued running into this issue.
Idolenz
It's a way to force people on the forum and to leave a paper trail that anyone can see. When a ref get's a request and concludes (be it right or wrong) this is a fake → denied, this instance is lost to the vast majority of people and can also not be referred to for future cases or corrections.
This I can imagine was a fairly valid reason in the past, but like Compendium said, now that you can post pictures in your sources, the likelihood of a newly added real year marked as fake by the referee is probably much lower. Maybe a trail in the forums makes sense for common counterfeits with nonexisting years, but those adding them to the catalog would almost entirely be inexperienced collectors who wouldn't even think to search through the forum in the first place. Now that I think of it, these added counterfeits would be on mostly recent coins too, and of course, that's if this would occur at all. If it does, it would be very infrequent.
Sjoelund
We have several times had the problem to delete a NON-EXISTING year, because how can you prove, that a year doesn't exist?
Any new years still have to be clearly proven to exist, so I don't see this being relevant to the removal of these pointless barriers.
Generally, I just don't see how removing these year locks, especially on most older coins, would create any substantial issues, whether it be for the referees or the catalog or whoever. Many, maybe even the majority of older coins that I have edited actually don't have year locks, and that hasn't caused any problems. It's the ones that do have them arbitrarily that cost us non-referees time when we should be able to change it like any other edit. As several of y'all have mentioned, the fact simply is that there's no point in preventing users from adding dates when they still have to be reviewed.
Thanks.