Strange!!!! I think number does not matter, person do LAWL Jokes apart..
We visit ISB and Pindi twice of thrice every month and our two cars are Lahore registered..... and our work is Faisal Avenue just near to Parliment house... we are never stopped by Police wala at any check point.... Never Ever...
and we have one ISB registered car as well, which is mostly driven in Lahore....
I use Lahore Motorway Bypass from Thokar to Band Road almost every week.... They stop almost every car their and luckly i have never been stopped their (not on LHR or even on ISB registered car) sometimes i am alone and some times with my wife and kid....
during night time i use a trick, which is really helpful while crossing these check points.... i switch of my car head lights totally on reaching the check point and switch on all the lights inside the car..... and they never stopped me!