Stan Prevost wrote:



It seems to be to everyone's advantage for the pilot to report being OTP as
soon as he is and can remain that way, even if that is on the runway, as
newps described, or on initial contact with Departure. That minimizes the
time and space during which I must be provided separation, as long as I am
willing to forego that.

If you report it prior to departure the tower controller can amend your
clearance in the computer and this will save a landline call to the
center. Once you tag up on the radar the tower/departure controller
loses the ability to make changes in the computer, only the center can
do it.