I do not like amex FR. I would close my amex accounts if they asked for those documents.
re receipts: After you purchase something it belongs to you, the store can make no policy that says you may not leave the premise until they check your receipt. If you know you did not steal anything, there is no reason to stop.....
Costco is not a "store". It is a club. They may not be able to stop you from walking out of the store, but they can revoke your membership for not following their policy.
I have been through the AMEX F/R and I didn't care for it. I fully support AMEX having as many details about my financial profile as they wish, but I don't think their manner of obtaining them is ideal.
AMEX extended me about $35,000 in credit, and when I started to use about half of it in the first 6 months, they got nervous so they F/R'd me. If you think about it, $20,000 of unsecured debt is a ton of money to loose. In some places of the country that could be a down payment on a house.
If you've ever had a mortgage, you'll know that they need paystubs, 4506T's and a credit report. Assuming you put 20% down on a house with a legit appraisal in a non-declining market, the bank is not going to loose anywhere near $20,000 if the house goes into foreclosure, yet they still want to see all of your documents. I'm actually surprised that more credit card companies don't want proof of income.
My problem with the AMEX method is that it is not up to date. If you get laid off in January of 2012 and you earn no money for 14 months, and then you get an F/R in March of 2013, you will pass with flying colors [because they will look at your 2011 taxes]. Or if your income goes up or down significantly, AMEX has no way of knowing, since they won't check your paystubs. This is a huge risk for AMEX and a huge disservice to people who have rapidly growing incomes.
I also think that AMEX should give you a courtesy $500-$1,000 limit when you are under F/R so that any automatic billings will go through and you can use the card for small purchases. Or AMEX should F/R you BEFORE they give you a credit card. Extending credit and then suspending it is not good business.