1. Only in certain situations... Downhill holes, and when there is an even worse hazard behind the green (OB).
2. I've seen them on a few Tilly/Ross courses, but I'm not 100% they are original.. they could easy be a product of one of the Jones remodels.
3. This is as close as I could find to a modern back bunker with a flashed face... DMK from the seldom seen Queenwood 16, England
for more of thoughts on back bunkers check out my blog linked bellow... (Shameless plug!)