Ethereum

All roll ups have an off switch.

Is this a true statement?

Most do have pausable bridge contracts still, yes.  Until stage 2 anyway.

1000 $DEGEN - can you point me to docs on stage 2?

Stage 2 is a definition used by L2Beat in their rollup classification system. 
https://medium.com/l2beat/introducing-stages-a-framework-to-evaluate-rollups-maturity-d290bb22befe

Basically means the system is entirely permissionless, and while upgrades are allowed, they take 30 days to go into effect to provide an ample exit window for users.