Do the Instructables employees try to make every instructable that's published? Answered

If you want officially-tested-and-confirmed designs, you're better off with one of the magazines which promises to test everything before publishing it. Of course you'll get many fewer designs per day, and you'll be paying them for the service, but the instructions tend to be a bit more polished as a result.

Here on Instructables... If in doubt, you could wait for someone else (or several others)  to confirm that they've successfully reproduced the project, maybe including their own suggestions of how to make it easier/better/clearer. Of course it may be quite a while before that confirmation appears, unless the idea particularly appeals to folks... but the alternative is for you to dive in and be that first person to try it out.

No.
There are about 30,000 instructables (today), and why would they?

L

Probably not. Some of the Instructables are long term, high skill projects, others are simply variations on existing Instructables, and a few are just downright goofy.
There has to be thousands of projects posted here and testing each of them would be a tremendous task, and I don't believe they have a staff anywhere near large enough to do it, even if they really wanted to.
I suspect that there some Instructables that never get read by the site staff. I would imagine that many of the staffers are like me and other regs here, I scan what has been posted, read the ones that interest me (I have learned a lot of things I never knew by doing so) and perhaps attempt a few that strike me as fun or interesting.

I don't know for sure but I seriously doubt it.  I figure most of them are spending their free time working on their own projects.