I have a staff member's old iphone. His account is in good standing and he's been on an upgraded iphone for quite a while now. I figured I would use the old one in my office as an ipod/internet radio, but I turned it on today and saw it said "Verizon" and had a few bars of signal. I turned off cellular but it's still there and freaking me out a little. Could this cause issues with his latest phone? Thanks.