Aw comon guys that stuff happens all over the place everywhere. Hell, I even know the police have a special "code" to say they are going to get some take away food or something.
Also know first hand that the police is quite doing a good job in getting rid of that behaviour. Well, can only tell whats happening here in Holland, I'm quite sure UK police force won't handle it that much different.
It's just a shame this happens, but there are a few rotten apples everywhere. And they are human too I guess and take advantage of opportunities like this.