Why the heck would they do that?
My guess is that they have chatter that something is imminent. They have massive police present in London.
So now each incident is being treated as if it is part of some big planned assault
Why the heck would they do that?
Because "officer safety" comes before whomever is left behind to be butchered by the Muslim Jack Nicholson's 'The Shining' character.
But don't worry -- Liverpool police are armed with several rolls of yellow police tape, chalk, and 5'-2", 100 lbs female officers armed with very large cell phones.