What is the best way to work out if a location in an AI's nav mesh is reachable by the AI?

Hi all. I’m trying to create a system for my AI to search for a hiding player. The player will be able to hide under objects, furniture, etc. For the system that I have in mind, I need the AI to be able to detect when the player is in a location that is can’t normally reach, e.g. under a table. What’s the best way to do this? Thanks for the help