True. Usually when creating a shell loop like this, I prepend 'echo' in front of 'ssh...' as a dry run first. I also wouldn't actually use something like this for commands that are destructive in nature. Usually it's for things like running informational commands ('rpm -q', 'uptime', etc). Of course anything can become destructive if you fat-finger it hard enough.
In short, use automation with care.
Exactly.
One-offs are easy to test interactively with cssh, and despite what anyone thinks, there are always one-offs in the real world.