Tablo devices have ALWAYS been passively cooled. We do extensive thermal testing.
You’d have to stick it in an enclosed cabinet with no airflow, sandwich the device between other heat-generating things, or stick it in your attic in the summer for it to get too hot.
And if it does reach beyond safe operating temperatures, then a thermal switch will turn it off.
There’s no need for fans or cooling racks or anything else as long as you give it room to breathe and it’s in a location that is comfortable for humans to be in.