I'm sure the control rooms do a very good job of whittling down the genuine requests from those who perhaps might perhaps (intentionally or otherwise) be misusing the system. Unfortunately though, the system isn't infallible and calls do get filed through for attention of the emergency services.
Where I come from, if anyone wastes police time they are dealt with accordingly and if they should repeat said time-wasting then a summons may be dropping through their letter box.
I should add that the use of the 101 number is to reduce the number of these types of daft phone calls to the 999 service. Hopefully the 101 number will stick in peoples minds better than longer 13 or 14 digit local numbers for area control rooms. Certainly makes it easier to dial I can tell you