If they wanted it to kick off they wouldn't have bothered with all that stuff at the Leeds game, just let it kick off then. Such a stupid theory.
They are trying to tread the fine line between enforcing order and being accused of overreacting.
An example of this was the Burnley home game where things were getting tetchy, so the police brought out the dogs. On that occasion they were accused of causing the trouble by being too heavy handed. They can't win.