Something like that used to happen when I lived in New Jersey. Monmouth County had a 'taskforce' we called the 'jump-out boys' because they'd roll around in beatup conversion and minivans and bust buyers and sellers. After a while, if you watched the parallel streets, you knew where they were coming from and where they were going. While they did do some serving of warrants, most of it was 'on the spot' type shit.