I'm reasonably certain the pun is a quantum physics joke:
In quantum physics, observing the event in question causes the waveform to collapse and actually changes the results of the experiment. Like Shcrodinger's Cat - until you open the box and observe, the cat is in a state where it is both alive and dead. Or as the first line ever of The Big Bang Theory describes it:
"SHELDON: If a photon is directed through a plane with two slits in it and either slit is observed, it will not go through both slits. If it's unobserved it will. However, if it's observed after it's left the plane but before it hits its target, it will not have gone through both slits."
Did I get it?