As with most police operations/investigations it's all about eliminating lines of inquiry or leaving them on the maybe pile. Once they have had a little look at you and established who you are / what you do / where you go / when you go and you are no potential threat, they rule you out and move on.
When building the bigger intelligence picture, every little scrap of int, no matter how small or insignificant helps. Like it or not, if you are in aviation, you are a piece in that jigsaw.
If the police have uncovered a plot to hijack a heli at a hotel in Lancs and I was a heli user visiting hotels in Lancs, then I for one would want the police to know all the details of my visits. Makes it very easy for them to put 2 & 2 together and phone me up on 'the day' with a "police operation on a xyz hotel today, Sir, I'm afraid you can't land there." Only later when you see the 'police arrest 3 terror suspects at xyz hotel' headlines, does the penny drop and you thank god we have people working so hard in the background!