Because of the Lisa Irwin case, I have learned more about cell phones, cell phone pings and triangulation than I care to. The thing with Elizabeth's cell phone, it would have only pinged if it was on. If she was only using it for games, I suspect it was only on when she was playing with it, to preserve the battery. If it was on, even if it didn't have service, even if she didn't make a call, it would ping to the tower every few seconds.
There was a case of a family driving from Seattle to Oregon who got snowed in on a remote logging road. It was the Kim family. Anyway, they were eventually able to locate the mom and kids because they occasionally turned the cell phone on, even though they were not able to get a signal and call out, searchers were still able to triangulate their location. Their story is here. . .
James Kim - Wikipedia, the free encyclopedia
Just an FYI. .. tonight I was asking my 10yr old, hypothetically, if she was approached by someone with a gun and was with her brother (who is just a little older) and the person put the gun to her brother and said, "Come with me." What would she do. She first asked, "Was this someplace in public or secluded? (because I always tell them. . no matter what, don't go with the person. They are not going to kill you right there. They want to take you someplace secluded and then kill you.) I told her secluded. And she said, "Boy, that's tough." She said that
she would not want to leave her brother and just run away to save herself.
Soooooo. . .we had the appropriate conversation that would follow that. If you go, you are both dead. You have to try and get away in order to have any chance of saving the other child.
Just thought that might be relevant here.