It's a good idea, if only you didn't have to go and stand outside the police station to do it.
This is where the idea won't work, in my opinion.
All those people hanging about outside the police station faffing about with their phones......anyone passing would soon know what they were up to. You're safer phoning from the privacy of your own home.....no guarantee of a speedy response so I'm told but safer.

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Old aunts used to come up to me at weddings, poking me in the ribs, cackling and telling me
'You'll be next.' They stopped when I started doing the same to them at funerals.