[thaumasiotes]

> I'm a bit worried about social engineering there. "Oh, it's a bunch of gibberish" may pass muster with a support rep (in both of your approaches), leading to compromise.

I can confirm that this is the case. I provided a gibberish answer to a security question for Blizzard. I didn't bother to write it down, relying on not forgetting my password.

I never forgot my password, but Blizzard shut down my account anyway because I was making payments with a card that was not listed as the account's "primary payment method". (The card I was using was listed on the account, but another card was the "primary payment method".) When I had to call support and answer my security question, the answer I'd filled in just meant that I wasn't required to provide the correct answer.

[zifnab06]

I've found it's better to give them correct answers that are entirely fake. The make of your first car is an astin Martin. Your nearest sibling lives in lunar colony 1.

This way "it's a bunch of gibberish" doesn't get past their security.