Thanks very much, Terra! I'm pretty much the same way with not commenting on other mappers’ work I'm not familiar with. It can certainly explain my low post count when compared to other regulars here. Maybe I should remedy that...
I tend not to worry all that much over missing things. There have been the few occasions where that's happened to me with previous map sets, but I don't stress over it. If it happens, oh well. I just revise the map and get it updated on the site.
When I'm in the labeling phase of mapping, I usually have a few walkthrough sites handy to make sure I don't miss anything. There have been times where I find something that wasn't listed on those sites, but it doesn't happen often.
Although I haven't formally announced it yet, I've been working on Light Fantasy on and off for several months, and if it weren't for this one walkthrough site I've been referring to, there would have been a ton of hidden items I'd have never known existed. I've attached one such map to this post. All the hidden items are found in the trees. If you weren't told about them, you'd never think to look there, right? I wonder if it's ever brought up in the game manual.
But even so, if I had sent in the maps without those hidden items pointed out, I doubt anyone would complain over their absence. I don't think this game is well-known enough to warrant that kind of response anyway. So in conclusion, I'd just say don't sweat it.
Trop, even if you manage to get your karma down to zero, it's still very possible to get it back up to 100. Every time you meditate at a shrine for leveling up you get 10 karma points, so stealing the odd thing here and there isn't going to make the game unwinnable.