Having a "EVEN_MORE_DANGEROUSLY_SKIP_PERMISSIONS" flag is exactly what I'd use. Maybe Anthropic saw the constant profanity in the prompts I've been sending after getting refused.
The variable alone, however, is kinda suspicious - I'd do both variable and command-line flag, just for extra assurance.
(another idea might be to enforce docker, but I know some people run agents in VMs, so this won't work)