What I see here:
- Don't give everyone root permissions
- Make important files writable by root only. If regular users should not modify it, don't allow it
- And... yes, don't allow any special characters in your prompt for "paste random stuff in my shell and run it" ppl. To be honest, I'd even lock those ppl out of the system. You could insert an invisible, uncommon char in the default prompt, detect it, and log the user out (after sending you an email ;-))
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