That's the last time she's called my house. I just looked up the call logs. So other than them going over every other weekend, she hasn't talked to them. They have not asked to call her.
On another note, they each got a prepaid cell phone for when they are out playing. They were told to only use it to call home to check in or in an emergency. They ended up burning 40 minutes calling each other.

And then deleted the calls from the call log so I wouldn't know what they had done, but I had been keeping track of how many minutes each phone had. So now they are both grounded.