Earlier quoted context omitted.
But you could drain out all the ETH in the Optimism reserve by asking to withdraw, since you've fooled the network into thinking you own an arbitrary amount of OETH? Which would keep working until the main L1 Eth network rejects transactions for transferring ETH it doesn't have?
The folks at Optimism would certainly hit the pause button on that withdrawal before it escaped, if there aren't already limits and automatic controls in place. It takes 7 days to withdraw L2->L1 via the standard bridge. (They have administrative controls for now during development, at some point they're supposed to turn it completely permissionless...)
https://help.hop.exchange/hc/en-us/sections/4405172442509-FA...
Edit: O...kay? Apparently the parent of this comment is aware of alternate, much-faster ways of withdrawing L2->L1, and what their constraints are, but still elected to leave those out and imply the one-week lag was a binding constraint?
(Would have posted as a reply, but my comment rate is getting throttled for some reason.)