Card limits slam credit scores: not fair!
Here's where it gets really bad: one component of your FICO score is the amount of credit you currently have drawn down divided by the amount you have available. Lowering your limits decreases the denominator and can quickly send your credit score plunging -- even though you didn't miss a payment, open a new account, buy a Ferrari, or do anything else to draw the ire of the credit gods.
So millions of people have seen their credit card stories go something like this: use credit card, make regular payments to build strong FICO score, see your credit limit slashed because of broader macroeconomic conditions, be required to pay a higher interest rate because of changes in your credit score caused by something the bank, not you, did. Oh, and you'll also have to pay a higher interest rate if you borrow money from someone else to buy a house, which cost you thousands of dollars over the years.
The conspiracy theorist in me thinks that that's exactly how it's supposed to work out: lend someone money, reduce the limit, and then lend them more money at a higher interest rate. It's brilliant!
I would be nice to see the Fair Isaac take some action to prevent these credit limit cuts from increasing the cost of credit for people who have behaved responsibly. Somehow I doubt that will happen.