I'm not quite following your logic here. If you're playing a public park the day after your disc goes missing and you cross paths with someone, you can't just assume that they're the one who stole your disc. It's a public park. Even with snow I doubt this guy was the only person to walk through there that day.
Unless there's more to the story. You guys made eye contact. Did he also stare at your disc bag? Was he carrying a stack of discs? Did he have a shirt that said "Stobaugh" on the back? Why did you find him especially suspicious other than his just existing in the park at that moment in the snow?
I assumed nothing. Thus, I did not say anything to him. The problem with the story is that I would have to tell more about the park for readers to realize that this park is rarely used outside of disc golf - and then, it is only used by four or five of us during the winter. It is a perfect square with roads on three sides and apartments on the fourth. Two of those three sides are residential houses with the last side having an elementary school. With the streets and sidewalks routinely plowed during the winter, and with no other activities in the park, there really is no reason for people to be cutting through, and thus, almost no one does.
During the non-winter months, a few more people cut through, a few more hang out in the rentalable shelters, and every once in a while someone lets their dogs off the leash (which is a no-no). Overall, everyone knows this is a disc golf course. And yet, in the winter, there are only four or five of us who play. That is the reason why that in every case of a lost disc this last winter, with the exception of mine in this story, has been recovered days or weeks later. Mine disappeared after an hour. In this particular case in this specific spot of the course, you have to go out of your way to want to cut through here.
My story really did not have moral beyond the convenient timing of this individual having taken the same path a few days in a row, creating a path in the snow, that makes no real sense of the way he was cutting through the park. He carries nothing with him and is not a player.
I also decided to say nothing because who knows what his state of mind is. I am not calling him thief, but I am pointing out the conscious decision to rip off the ribbon and leave it there (I put those ribbons on with multiple layers so they last all winter despite numerous tree hits). I am also pointing that this individual saw me playing the next day, I was almost in the exact same spot where the disc was left, and I had out some discs with the exact same ribbons visible. He chose to say nothing - not that he was under any obligation to say anything.
I am an introvert of a high degree, keeping my boldness to occasionally typing on the internet. I chose to say nothing because I am only 90% sure he was the one to pick it up, and being that much of an introvert, had decided was not even worth the effort of asking because that same introvertness assumes that he was already going to say that he had found nothing.
What is the point of the whole story, I was relating a time where I left a disc behind in the middle of the fairway in a spot that was not likely going to be discovered because it was almost dark in a part of the park rarely traveled by non-disc golfers. I expected it to be there when I came back for it a hour or two later. Instead, I found the ribbon that was evidence that someone else had found it, ripped the ribbon off, and left the ribbon where the disc was. The next day I saw something taking the exact path that had to be taken in order to find my disc. No one else takes this path. He chose to say nothing; I chose to say nothing. I purchased two more discs to replace that one. Not a theft story, but definitely a story of someone taking my disc from the middle of the fairway with no apparent attempt to get it back to the owner.