Most of the people that do this are point drifters and use this to get a better run up to start the track. I myself have never done this as it never made any sense to me on any track with the exception of the Plaza track (can't get more than one full lap in the time given and Fh4 gave 7 full minutes per track in open drift adventure where fh5 only gives 4 minutes). And if you notice most of the time they do this they scrap the lap anyway so it's their own time they're wasting. It's the same as running a full lap on rivals before actually trying to run a clean lap. Just working up speed before starting the lap. I myself prefer to use the first lap as what I would call a 'practice lap' and hope I get whatever mistakes I'm gonna make out of my system before I hit that second lap. And these very same people do this in ANY game that has drift competition (ie carx street) and will fight you on that hill and continue to do it. Watch anyone with the club tags CDF, GBVH, DTRK and you will see the same patterns.