Well that would be a breach of Article 20.2 of the Sporting Regulations, specifically the bolded parts.
Drivers must use the track at all times. For the avoidance of doubt the white lines defining the track edges are considered to be part of the track but the kerbs are not. A driver will be judged to have left the track if no part of the car remains in contact with the track.
Should a car leave the track the driver may re-join, however, this may only be done when it is safe to do so and without gaining any lasting advantage.
At the absolute discretion of the race director a driver may be given the opportunity to give back the whole of any advantage he gained by leaving the track.
A driver may not deliberately leave the track without justifiable reason.
I don't see why the laptime shouldn't be deleted for a breach of Article 20.2. It's not just the lap you go off, it's also the lap on which you get an advantage from the way you rejoined, that falls under Article 20.2.
There's a precedent for this - in qualy for the 2000 German GP at proper Hockenheim, Heinz-Harald Frentzen was about fourth or fifth out of the pits at the start of the session. It had just started to rain, so everyone was desperate to be first to get around and start their laps, and Frentzen overtook the guys ahead of him by cutting the chicanes on his out-lap. The stewards deleted his fastest laptime. He started 17th.
Edited by redreni, 18 July 2014 - 20:30.