My next thoughts are quite "out there." CIA recruitment? Is it possible that SK spoke with someone at a CIA career fair at the Univ of Ut? Or during his internship with Utah Governor's office? I know, I know! Yet, does Steven have the qualities that the CIA searches for? He's college educated, bilingual, spent time in Brazil, and doesn't have a criminal history. If this is possible it may have taken the gov't years to perform a security clearance.
I don't really think this is the case, but everything seems in until it's actually out. And, what better way to stage his disappearance than to have him last seen on a security camera in a quiet neighborhood. I have no doubt that our gov't is capable of anything & everything. But, is the CIA something that Steven would have interests in? It can be very attractive to someone who is searching for a solid career, or a way out of a life that may appear to be going nowhere.
I don't know about this, but I just wanted to get these thoughts out there.