I agree. It's also the case that understanding often comes from changing. So in a sense the fence is just a blanket "never change anything". That's obviously ba

I agree. It's also the case that understanding often comes from changing. So in a sense the fence is just a blanket "never change anything". That's obviously bad. I think a more reasonable approach is to change stuff in a conservative way where you limit the blast radius. Like running something like Ruby's scientist library on the new code.