Since from some time to now we are seeing people crashing into other drivers after finishing the race (like today's WT race), I want to remind you what the rules says about this:
http://www.formula-simracing.net/racefiles/Rules/2013 FSR General Rules Document.pdf
I hope those who never read the rules (so basically 90% of the drivers) will understand now that it's not allowed to do such things, even if the race is over.
12. Race Procedure
12.8 After crossing the finish line, the drivers can drive a parade lap back to the pits or press ESC as soon as they want. Drivers are not allowed to crash in to other cars or walls while celebrating/mourning the happenings of the race.
http://www.formula-simracing.net/racefiles/Rules/2013 FSR General Rules Document.pdf
I hope those who never read the rules (so basically 90% of the drivers) will understand now that it's not allowed to do such things, even if the race is over.