A BG would be ideal for a social run...but we couldnt keep stopping and posing for photos and having a chat.....well...merry couldnt anyway.
BUT...we wouldnt all be together if it was set around merrys BG as we'd obviously be on different legs (but if it was a race we wouldnt all be together anyway).
But #2.....if it was on the BG we wouldnt be able to do a social thing after it because of the time differences we'd all be running...whereas if it was a race it would give everyone the chance to be together in the evening.