Today's Reds-Rockies game is televised on MLB Network, with Greg Amsinger doing the play-by-play, and former MLB pitcher Mitch Williams working as the color commentator. Williams, nicknamed "Wild Thing" during his career, seems to be a bit off with his knowledge of the rules of baseball as well.
In the second inning, the Reds' Drew Stubbs hit a flyball to deep left field, and Rockies outfielder Carlos Gonzalez unsuccessfully tried to keep it in the ballpark with an admirable leaping effort. Gonzalez came very close, with the ball touching his glove. The glove also touched a fan in the stands. However, the ball was clearly behind the wall when the fan touched Gonzalez, meaning the fan is basically entitled to do whatever the hell they want.
Photo evidence of the play:
And a clear explanation on why such a play would not be fan interference from Wikipedia:
Note that spectators are allowed to catch a ball that is in play when the ball has broken the plane of the spectators' side of the wall, even if in doing so they interfere with a player who is also trying to catch the ball. In the 2003 NLCS, Steve Bartman famously hindered Moises Alou from catching a foul ball, but because the ball had already broken the plane of the wall, it would have landed in the stands and Alou would have had to reach over the wall to get it, no interference was called. The area where both fielders and spectators are legally allowed to catch the ball is colloquially called 'no man's land'.
Mitch Williams is apparently unaware of this rule though, and went on about how the play could be/should be fan interference:
"That could almost be considered fan interference right there." "Honestly, if they went to a replay, they could actually call that fan interference."
Amsinger then questions Williams' last comment by saying, "Ya think?"
Williams: "Yes, most definitely they could call that fan interference."
Later in the game, Stubbs comes to bat again, which of course brings back the discussion of his home run from earlier. And of course, Williams continued with the fan interference talk(which also made me want to slam my head against a brick wall for an hour):
"I think it was fan intereference... but nobody threw the red flag or appeal or anything."