So, I didn't get SSSS after-all. For the last few times, I know (think) the reason why I got SSSS is because on a single ticket and same date, I am flying in and out of the US from Canada. i.e. YYZ-ORD-LAX-YYC-YVR and same on my way back. So I got SSSS both ways. This time, I am staying in the US for the last few days, but this time maybe because I had 2 separate ticket, AC to the US DCA and the UA to ORD. When I check-in online on Sunday for my Monday flight, when ask for my address where I will be staying, I put a ORD address. So maybe the computer go why would someone only flying to DCA put a ORD address. Anyway, just happy that I am not SSSS today as I have a tight connection with terminal change at DCA.