I have 3 cards right now and received the 5000 point 1st use bonus on all 3 cards but the 1st stay bonus only applied once. I called several times to ask why the last 2 cards never received the stay bonus and was told each time that only one 1st stay is allowed per SPG account no matter how many cards you. They also seem to lower the credit limit on each additional card but you could call to get them to transfer some of your credit limit from one card to another.