Just an update on what I've been up to. The idea first cropped up from the WA fixes and was brought to my attention by @tryguy in post #34 in that WA thread. If it happens once, it can happen again, right? And indeed it did.

I also took the opportunity to look for the double-placed road, but so far - nada, zilch, zero, no cigar.

http://www.youtube.com/watch?v=kKLW-_tI0wE