Talking about the likelyhood’s of things happening i think another aspect is the way the people attending the party act too. For instance if you vandalise everything in sight, make un-necessary noise so as to disturb residential areas and poke fun at the police by throwing objects and insults .. Then they are more likely to take action and impose things such as what BioTech listed
It winds me up a treat when party goers disrespect their surroundings and other people – police or not.