The Legend of Korra

But still, vibrations travel through metal too and should be able to be sensed too. Depending on the rate that vibrations travel through differnt materials, maybe even better sensing. I just find it weird that a senser gets surprised in an episode when she should have at least sensed someone was coming, while a non-senser (Tenzin) just turns around and owns the guy. I mean Toph could sense, although the view was fuzzy, through sand, but she could still sense something at least.

Uh hello, have you seen that stache Tenzin has?