This is more than a just papercut actually, it’s really annoying.
I agree, i often need several try to find the right combination, may be a visual correspondence will be helpful.
Yeah, I lobbied, ineffectually, for strict UVN by default and some flipping tools in the UI… I’ll add this example to the heap.
That said, I am having a hard time making this fail - unless I use a shaded viewport and do not pick on the edge, but on the surface near the corner - I think Mitch, you picked near but not on an edge of the cylinder in your first example and the location happened to be nearer the short edge. I always click an edge, myself and it does seem to get it right most of the time in V6. I think seam edges might be a poor choice.
But all of that. imho, shows that it really does not work well in real life, I’m still in favor of UVN and some UI.
thanks,
-Pascal
Hmm, now I see that the V5 prompt is this:
Base surface - select near a corner ( Copy=Yes Rigid=No Plane ):
And the V6 prompt is this:
Base surface - select edge near a corner ( Copy=Yes Rigid=No Plane ConstrainNormal=No PreserveStructure=No )
Never noticed that change… Old habits… 
However, it’s a lot harder to target the edge than just somewhere on the surface near the corner…