The problem is that you can't prove a negative.

In this case, even if you saw it, it does not mean anything. You see, if you saw it, (according to the Madela theory) you would have been in the universe where it happened.

The other side that says that it didn't happen have to be able to prove that it didn't and how can they do that? It is possible that they didn't happen to see those shows or that they have simply forgotten or anything at all.

So, how do we know? But, just because you saw it does not prove anything except that you were in the universe that it happened in.