It's a better idea than sticking a DC voltage through the drivers. And easier.
is that bad for the speaker?... putting a continuity tester across the +/- of a speaker.
I use this method all the time for checking if speakers/headphones/microphones are still working (to see if the coil is still complete).
Can it cause any damage to the any of the components?? Ive never found it to do any damage and it certainly woks for testing purposes.