Been riding Time ATAC pedals on multiple bikes for well over 15 years. I have always had a lot more bikes with Times equipped, than shoes. As a result, I have numerous brand new cleats still in the plastic bag, well over 10 years old (since I generally only have about 3 pair of cleated shoes I use between all my bikes). I have been 185 pounds plus gear for as long as I can remember.
Accidentally unclipping has never been an issue for me. So has not unclipping when I want to.
Are they perfect? Maybe. Or is it because I have been using them on my daily road bike commuters (including a fixed gear), and mountain dedicated bikes for well over a decade, and have amassed a gazillion miles on them over that time, resulting in me knowing them inside and out? Maybe. Maybe a bit of both.
As for worn cleats, AFAIK, I am running cleats that are 15 years old on my go to shoes. I have them positioned on my shoes in the easier of the two positions to release. As you likely know, with all Time pedals, you can switch them to make the side rotation greater before they release - I have never found the need, even with these ooooooold, HEAVILY worn cleats I still use, to do this. In fact, BITD, there was a bit of a cottage industry on eBay, where you could buy old, worn out brass Time cleats, because noobs felt more comfortable using them.
If they ever started releasing accidentally, I could always switch them between shoes (left to right, and right to left) and increase the effort/side rotation required to release them. Maybe that won’t help with heavily worn cleats that DO begin releasing accidentally. I don’t know. God bless anyone that can amass the mileage required to wear them down to that point.
I understand that the newer Time pedals are nowhere near the quality of the older ones. I do have a pair that are about 4 or 5 years old or so that I am running on my fixed gear, that my LBS gave me for free (they were lightly used demo pedals when I got them). I haven’t had a problem with them, but they only see pavement and light duty commuting dirt. But they are on a fixed gear, so there’s that I guess.
As an aside, I have a bearing kit I bought probably 10 years ago that I still have not had to use.
TL; DR - there is little to no risk of Time pedals accidentally releasing, even using 15 year old, worn out brass cleats in the easier releasing of the two positions you can run them, on 15 year old ATAC pedals. Confirmed user, but only of older Time pedals. I can’t speak to anything manufactured in the last 5 to 10 years, because I run older ones that will. Not. Die.