So one person closing one card and product changing another card would lead to a shut down? The post was for 2 different people, not 4 accounts for the same person. Although, even if it was all for 1 person, I don't think it would necessarily trigger a shut down unless something else was going on the OP didn't mention. The OP has to be under 5/24 to apply for the cards he/she is interested in anyway. From what I have read, there are still people getting approved for 4 or 5 Chase cards in a year if they start out at 0/24 or 1/24.

I doubt that the OP is at risk of shut down for closing one card and then applying for a different one 6 - 12 months later. If so, they would have shut me down already!