I think it depends on how many horn-hunters, coyotes, wolves, grizzlies, etc. are in the area. The elk out here don't have chance once they drop a side...chances are, somebody's watching.
I often wonder the same thing as you, but with bucks. I watch bucks often and will see them with one side or no sides eventually. When I go in later (so not to spook them) to find their sheds I either find boot tracks, or find that their sheds are nowhere close to where I watched the buck. I think when it's time for them to shed, they run for about a mile or two away, shed them, then come back to their spot!!
Hmmmm...
Huntemup