After the game has ended a.k.a the final whistle has sounded, yes you're right, and I don't think they'd even try.
But before the game has ended, they will absolutely stop you, and probably make an example out of anyone disrupting a game in play. All im saying is, its hard enough getting a job as it is, without a caution to your name as well. If that's what happens to some, then I wonder if it will be worth it?
It will be a party and a great day out regardless.
From being a police man the police will not hand out warnings they will charge and submit a report to the procurator fiscal as per ACPOS guidelines. The police no longer have the power to issue formal warnings. So anybody caught on the pitch before final whistle will be charged and reported to the procurator fiscal and it will be them who will decide what happens