Are one way tickets still an SSSS trigger? A few years ago, I constructed a round trip out of two separate one way tickets on different airlines (which were not in the same alliance) because it was much cheaper that way than any other round trip that fit the schedule. No SSSS in either direction.
Another time, I did a similar thing because I could use a one way award ticket on one airline, but another airline offered a more convenient and cheaper return flight. No SSSS in either direction.
My understanding is that they've relaxed the requirements that airlines give SSSS to passengers that have frequent-flier accounts that are over a certain number of months old and/or have a certain amount of activity. That would exclude most FTers as long as they are flying their preferred airline or alliance.