That only works for remote support type calls, you'll get opposite results if you try those tactics with free cruise or fake credit rate adjustment calls.
I finally got one of the credit rate adjustment calls to not immediately hang up on me, kept them on for about 15 minutes.
They incorrectly claimed that I only gave them 15 digits for my credit card number-- I think to make sure I read them the same digits back. Next time I'll make sure to have a fake credit card number handy that passes the checksum.
