The point is the countless dress rehersals on a frequency that should be reserved for the real thing.
Actually they are not countless and they should not be reserved for the real thing as you would find out if you visited D & D at West Drayton.
D & D are quite happy with practice pan calls, as one of them pointed out to me the other day it is also practice for them as well.
FBW
PS However chatting on 121.5 is extremely frowned upon