"Checked a location" == Looked in the container/killed the mob. I'm not sure under what circumstance you can check "your" location and not see the wand, but I believe this happens if the wand is in a container, and someone grabbed the wand, and there hasn't been an area repop since then. I am sure that there is a simple coding solution for getting rid of that problem, but I don't know the exact mechanics of the system, nor am I a coder so if that is false, sorry.

If you check a location and don't find it, yes it is off the list. Otherwise, you could just check the location you wanted over and over.

Detect artifact plays with it like this. If you cast detect artifact, and whatever factors go into if detect artifact fires or not work out, and the result is a positive, then detect artifact triggers the "15%" check. If you fail the 15% check, detect artifact gives a negative result. If you make the 15% check, detect artifact gives a positive, and that location is now yours.

If the detect artifact explanation isn't coherent, I might be able to phrase it better.

Once again, I think this system would closely prevent abuse. If the numbers (15% vs 20% etc) aren't public, it would be VERY hard to figure out how to statistically maximize the chance of getting the wand loc you wand, and even if you do maximize the chance, you will still fail to get that location a good chunk of the time.

Also, this system rewards "real" exploration MUCH more than the current, in that if you don't have a wand, you know you have a decent chance of finding your sleek if you go exploring, whereas with the current system you have a relatively low chance of finding your sleek.