What, from a switched on mobile phone in a light aircraft??p
Probably OK if VFR, surely, provided you're not relying on a VOR for navigation? And you will be VFR, if doing the circuit-over-girlfriend's-house routine.
Or is there evidence that they interfere with more than just the VHF radios?
On the main point, the message I get is that if I ever feel inclined to want to wing-waggle I'll practice it first at altitude with an instructor on board, then decide whether or not I feel like doing it near the ground on my own.