This behavior is far from suicidal. By and large it has to be a money making venture for the bank, else they will not keep it going as long as they have.

Just consider the fact that about 6 years back Chase and Wachovia were giving huge amounts of UA miles for opening HELOCs. We opened the HELOCs, took out large loans and wired back the money the same day/next day. That amounted to an average of ~300K miles for <$100 in interest and other fees. Some FTers did this repeatedly on multiple properties and raked in a couple of million miles each. Banks did not go down because of this. They went down by losing hundreds of billions on sub-prime loans. These mileage bonuses are chicken feed to them. And the number of people out to collect miles is very small compared to the total CCs and new accounts coming their way. It is the cost of doing business. Some people will use the loopholes and it has to be accepted for the larger goals they have set for themselves. So I would not lose any sleep over Citi offering some promotions. Their stock did not go down from $60/share to <$3/share because of promotions.