90% of the times I've seen police and stewards wade in heavy have been games where smoke has been let off. I'm not saying it's the only reason but it plays a huge part. If the Bois have such an issue with the police going in heavy then surly it would make sense to do as little as possible to provoke them, i.e don't set off smoke bombs. Either set off the smoke and face the fallout from the police, or don't, behave yourself, and the police will leave you alone. You can't have it both ways.