You could really make a fool of yourself!
The only times I celebrate before the full time siren is during a bye week and even the Chargers and Sharks have found ways to push these into extra time.
I was always taught at high school that the finish line was 2m past the post and to stop running then. Normally by the time I had run 2m past the finish line a man called Nic Barr was waiting there to shake my hand, having had a cup of tea and written a thesis.
Here are some fun examples where individuals have definitely celebrated too early with horrible ramifications!