> There was no crowd around him, no stage, no conference lanyard

The crowd, stage, lanyard — those are indications that "you can talk to me" or "here I am, this is my name, I'm speaking at this conference". Wearing a lanyard is an invitation.

> In one of his videos, Salvatore mentioned an upcoming local tradition: the Rietina di Campobello di Licata

> It was pure, absurd coincidence

It absolutely wasn't. He mentioned it, but politely declined meeting up, the author drove there anyway.

> just Salvatore on his evening walk in his hometown

I think it would have been courteous to leave him alone