Putting an actual name in there is probably a lot safer than anything that might be described by a human as "just some gibberish". Pick an uncommon name, maybe from another country, maybe spell it in a different way, as long as it's still recognizable as a plausible name. Most operators wouldn't fall for it if the attacker says "just some random characters". The important part is to not reuse the name between registrations.
Combine this with similar unique answers to other questions and the chances of someone guessing them all become really small.
One thing I never tried is to just put something like Anyone_trying_to_reset_this_password_is_a_hacker_DQWIqw12E^1&UTFD@&$. Might be an inconvenience if you actually need to reset yourself.
If you use any kind of name you run the risk of it being guessed. Use a passphrase generator to get something completely random and easy to say over the phone.
Combine this with similar unique answers to other questions and the chances of someone guessing them all become really small.
One thing I never tried is to just put something like Anyone_trying_to_reset_this_password_is_a_hacker_DQWIqw12E^1&UTFD@&$. Might be an inconvenience if you actually need to reset yourself.