Tim Cummings, the designer of OzGAP 2005, writes:

It would be good if it wasn't a points penalty but rather a time
shift. We are trying to make this fun for new pilots. Many won't fly far so
won't have a lot of points to lose. If the timestamps for their entire flight
were pushed back so that they effectively started at the first start gate then
they need not to lose any points and they won't get an excessive number of
leadout points. The top pilots don't want to see new pilots leaving early and
stealing all the leadout points. The new pilots score their actual speed into
goal but because they are flying during the slower earlier part of the day they
won't be stealing the speed points of the better pilots. There newly calculated
Arrival time will also be later than that of the faster pilots taking the first
start gate so they won't be stealing the Arrival time or Arrival place points.
Everyone will be happy and no points penalty is required.

In terms of the benefits for new pilots flying in competitions, I found it most
instructional for me when I was out flying the course when a top pilot came in
underneath me. I was able to stay with him for a couple of thermals until he got
away and then the next top pilot came in underneath me. Now I see the new pilots
at the start gate watching the top pilots fly away from the start and never
being able to share a thermal along the course.

I implemented this time shift method in OzGAP 2005 in SeeYou and
it has been used for years for scoring US competitions.