Comment 4 for bug 984640

This feels like a feature since we're discussing changing default behaviors. I'm not sure its appropriate to land this in galapagos. We're also in quite a time crunch for Galapagos, and I think this one needs some careful consideration.

Once we make the default to fail on pre-flight check, it will be a bug to move forward without a --force or --shut-up flag, and then we may find later that we in fact want scripts to always move forward rather than fail in this way.