SSSS and foreign airlines
 

Do foreign airlines departing from the USA have to use the same SSSS system that domestic airlines do? (i.e. do they use the same no-fly database and/or randomly select pax?) What about when the airlines leave their home countries for the USA?

On an OS flight ex-JFK last week, an Egyptian pax had a handwritten "SSSS" on his BP. I wonder if this was random, or on the basis of nationality, or because he was acting suspiciously at the ticket counter.