How should rests be handled inside the Tomb of of the Nine Gods?

I’m running Tomb of Annihilation and my players have finally arrived at the Tomb of the Nine Gods. As they have been deciding when it is safe to take short rests, I’ve been rolling for random encounters, only to realize that there don’t seem to be random encounters inside the tomb.

This appears to give a lot of leeway to the DM regarding how often to allow short and long rests. A generous DM could allow a short rest after nearly every major encounter, while a sadistic DM could interrupt the party’s long rests, not let them recover spells and other long rest refreshing abilities, and maybe add levels of exhaustion to boot (for lack of sleep).

The only guidance I can find in the adventure is the following:

Arguably, it is always up to the DM how to manage rests, but many published modules use randomization as a way to balance between cakewalk and death trap. How should the be handled inside the Tomb of the Nine Gods?