Yes, you'd think scientists would see that coming.
I understand Schrodinger's cat and the double slit experiment generally but don't understand their relevance in the context of the show. The"point" of both is that "how things turn out" seems to depend on whether there is an "observer" or not. In the case of the double slit experiment researchers use particles that pass through a double slit causing a pattern to develop on a screen beyond them. The presence of an observer (I believe in the experiment this is some kind of sensor) changes the "behavior" of the particles and therefore the patterns produced.
There is an observer to the flash forward experiment - the guy in the stadium. But I'm not sure how that may have changed what happened - if that is what Simon is even getting at. Of course the observer may not even be a person.
But no idea - and the writers may not have a good idea about this either and just be throwing out some scientific theory that will sound suitably mysterious.
The whole thing is kind of like asking if a tree falls in the woods and no one is there to hear it does it make a sound? There are a couple ways that I can think of that Simon might be talking about. One: Simon and his colleagues access information about some future secret event that is coming. They want humanity to hear the sound, to observe before it's too late. Two: Simon considers the flashforward experiment to be 'opening the box'. Before, the future could be thought of as both alive and dead. Now it is observed.
The first thing I thought of when he mentioned both experiments was the Big Bang Theory.