This is also my preferred method, I also like the calls from my bank/CC company (maybe) where they want me to confirm my security details to prove I am who they believe I am, I refuse to answer any questions & ask them questions to prove they are who they say they are, to which they always say they can't tell me that until I have answered theirs, to which I say I can't until they have answered mine, you can see where this is going, best I have managed is 15 minutes with a possible Halifax employee.