The one time I've had an issue is when I was online one day, updated my address from Ohio to Montana, and then requested a new card. They sent the new card to Ohio, and I didn't get it, so I called wondering what had happened. They ended up having to cancel the account so that card wouldn't get used, so I had to get a new card. To their benefit, they sent the card for the new account express through DHL, and I got it on a Saturday morning. (Oh, and my credit limit is a bit irksome.)
Anyway, the reason for my praise now is that I just received a letter from their fraud protection unit, saying they tried to call but had no luck, so I should give them a call back. I call, and find out they still had my parents' number on the account, so I update that. She then verifies my past transactions, starting with the laptop I bought earlier this week (I charged part of it to my Discover), and then transactions since then, which included Bresnan, Real Food, Fuddruckers for dinner last night. Apparently charging close to $1000 on my card set off thier fraud protection algorithim.
I'm guessing I didn't trigger the one for my bank debit card because I use that account to pay my Discover bill, so a large purchase on their isn't unusual (though my credit card bill last month was huge since I had bought my ski pass and plane tickets on it - I wonder if it didn't trigger because they've got it programmed to include holiday flux?)