It is pretty well impossible to discover a planet by occultations. For one thing, in most parts of the sky the density of stars is pretty low. People do study

It is pretty well impossible to discover a planet by occultations. For one thing, in most parts of the sky the density of stars is pretty low. People do study occultations by known distant objects -- that provides some of the best available info on physical size and presence of atmosphere for KBO's. But in most parts of the sky, it is years in between occultations, which last just minutes. You have to be looking in the right place at the right time. And the sky is full of variable stars, so just looking for changes is hard.