Unless the plot calls for the live powerlines set fire to something, an over-laquered arbor for example. (c.f. Meet the Parents)
A discussion concerning this can be found here. Oh, and your mention reminded me of why I refused to see the new Godzilla movie: this huge lizard is stomping around in NYC. Why do I not hear any car alarms? Those annyong things can be set off by the vibrations of a passing bus, but not the small earthquakes caused by a giant lizard?!