Yes, there are many reasons why an editor would go to a site from the "unreviewed" queue, and then neither list nor reject the site. I do it quite often. Some possible reasons:
-- it needs to be sent elsewhere (possibly a category in a language I don't speak), so send it there (still unreviewed)
-- it looks like a great site, that will need to be reviewed thoroughly and then sent to 2 or 3 other categories (possibly in other languages) sites for listing.
-- it looks like an affiliate site, but needs more investigation
-- oops, my boss just walked in and wants to talk about remunerative work.
-- oops, my wife/child/... just walked in and needs the telephone NOW.
-- oops, I need this browser window to do more research on a site I'm reviewing in ANOTHER browser window.
-- oops, this site (or the site in that other window) crashed my browser. (Bill Gates and All His Demons are Alive and Well on Planet Earth.)
-- oops, the site doesn't crash my browser, but it does demand plugins or extentions that I don't have.
-- the site abuses its visitors with popups/graphics/interminable download times/excessive banner ads or any of 50 gazillion forms of REALLY REALLY bad web design.
-- Aargh! I can't stand another second of this! I need to see living things: birds, flowers, grass, trees, fungi; I can't stand the lint buildup in my navel a second more; dinner is long overdue, etc.
There really is no way of second-guessing the editor. But if I had to bet -- and I could bet without the danger of ever finding out whether I was right or wrong -- my first guess, for a site in a Regional/Europe/France category that had been quickly and briefly visited twice but not listed, would be ...
"The site is in French, or primarily in French, and was therefore quickly sent to Test/Misplaced/World/Francais, for sorting out by someone who knows French."
It's worth repeating this, not because I want to know about this site, but because this is a very common submittal mistake, and one that causes both maximum site delays AND maximum editor effort. First we have to figure out what language it's in -- often not obvious to, say, American editors; then the editors in the right language have to find the right category in that language -- which may be no easier than for an English-speaking "Arts" editor to find the right "Computers" category (or vice versa).