"pick up card" means that the card is a stolen card, and if presented in person, the merchant is supposed to try to retain the card. It's rather pointless on Internet transactions.

The others I don't know, but I could hazard a guess on "score decline"... I know that many fraud screening tools use a combination of factors -- the country where the IP address of the cardholder is located, size or frequency of recent transactions, type of transaction (what kind of merchant), and assign a score to each of those factors relating to how risky the transaction is. When it hits a certain threshold of points, the transaction is declined for risk reasons, not because the card is bad or overlimit.