[sickoflibs]

RE :”We live in the SF Bay area. The friend in question moved here from New York a few years ago and is probably registered in NY, plus at two addresses here in Calif. The question is, what can or should I do? I certainly don't want her votes cancelling out the votes of me and my wife.”

Easy.
Move to Ohio, or PA, or FL. Your vote wont count anyway even if she didn't vote, nor will her 100 if she votes 100 times in CA and NY.

[Rusty0604]

I lived in CA until a few months ago and I know a lot of libs that thought it was funny to commit voter fraud to get propositions passed ( usually public employee union issues )and for local candidates ( because they are the ones that give the public employees all the goodies). So it may not matter for the presidential vote but it may for raising your taxes and any other crazy unimaginable thing they come up with.