That could be true but OTOH, Pablo the cocaine kingpin, was tracked by his cell. He just couldn't give up his nightly calls to his son. You can't assume anything. And say for example he grabs someone or breaks into a place and that person WAS listening to cell app, well there ya go. Let's keep the cards close to vest for the deputies sake.
Dorner's beef is with LAPD. I'd be surprised if he kills non-LAPD related persons. He's too intelligent, he doesn't need to monitor a live feed or listen to a radio in his possession. It appears to me Dorner is executing a well calculated plan that will not leave any type of trail. Perhaps he may have an accomplice or two.