True. but usually people have the direct plug types that are physically in the wall socket itself, and a long USB cable. The other kind isn't as common for muggles.
Also, considering she had a burn mark on her hand, I think I'm right.
Granted, it could have been a situation where voltage hit the water, and the current returned through her, her hand, and then neutral on the phone end itself. But that seems moderately unlikely.
Also assuming the house didn't have GFCI...