It's less annoying than the explanation for why the power went out, but still, got a
out of me...
Perhaps we'll assume that everyone they showed the power coming back on was wired up to the Hoover dam or a wind electric connection - both of which would instantly work in that scenario.
Know you're just being cute, but they DID show power coming back across the whole country. Also, Life After People addressed the Hoover Dam directly. Walk out tomorrow and lock the door, and the generators fail in about a year, turbines get trashed. so no...
Just little things, I guess. Kinda like in Defiance, they keep showing the St. Louis Arch. In the show, it's damaged but fine. SyFy keeps showing it in the promo missing a big chunk of the top. Looks cool, but fails basic math. Without the top (you know, the keystone), an arch won't stand up. Come on.