Yea, I've had similar things happen to me. I've been pulled over before for going 10mph over the speed limit and had 3 cop cars eventually show up, including a K9 unit (wasn't used, either). They ended up giving me a warning.

I think it's more about giving the appearance of 'no nonsense police', rather than serving any other real purpose.

I noticed a similar example the other night. There were a string of murders in DC and of course the police held a press conference about it in one of the neighborhoods. The policewoman speaking was going on about how they were going to increase patrols, put more cops on the beat, and make use of every last resource...meanwhile, she was surrounded by 20-30 police officers just standing around doing nothing and looking completely bored.