Indeed, Glek.
So Wally, why do we have TCAS if, in your words, "it isn't the answer in a SP environment"? IMO, it's absolutely essential in a single pilot environment, particularly in the airspace which the RFDS is operating, and the workload under which the RFDS's pilots work (you should know). In this case, see and avoid failed yet again. They were lucky this time. IF the pig had a transponder, then it's likely the near miss wouldn't have been as "near", as the RFDS aircraft would have been made aware via a TA or RA.
And that would have been a good thing.
IMO, the above example is a very good reason to have TCAS in a single pilot, high performance turboprop aeroplane.
In fact, why do most modern airliners have TCAS, when they are all multi-crew, Wally? TCAS has saved my bacon on a few occasions (even though we tried to separate the old fashioned way. Sometimes that just doesn't work, for a multitude of reasons.
The whole idea of TCAS is that it is the last line of defence if all else fails.