Comment by MiyamotoAkira

That's interesting. Whenever I have an issue with a flag it gets picked up on dev/test/uat environments (all gets tested, especially around the code behaving the same as before with the flag off). The code change never reaches production. And if for some reason the code under the flag is wrong, and it has reached production (something unexpected, unseen), undoing the change is whatever long it takes to switch the flag back (and the cache to update if you have a cache).