Chase, not surprisingly, has suddenly begun to tighten up all aspects of their credit operations. I have a Chase UA Mileage Plus Visa that I have routinely used to buy air tickets. Recently, however, I purchased a Biz HKG ticket and it was put on hold by Chase. I called and the hold was lifted. The UA agent said it happens all the time now--they're used to it. Mostly for tickets purchased to Asia and Africa.