The current tooltip requires a lot of background knowledge to understand(what is a rejection condition?). Also it could highlight the intent when can it be used or what can be the outcome. In the end more people could understand what it does and when to use it.

Current tooltip:

When enabled, the receivers movement should be considered a valid rejection condition.

Suggestion (doesnt have to be this exactly):

When enabled, for moving objects global illumination will not be calculated over multiple frames. Might reduce ghosting but introduce noise.