If I get into your non-privileged account I can set up a program that acts like sudo and I bet 99% of people will never notice they just gave their password away. And even if they do it's too late anyway because I've just compromised root and locked everybody out and I'm in there shitting on the filesystems or whatever. Because root can do anything.
And if I can't break into your non-privileged account then I can't break into a privileged account either.
These artificial distinctions between "non-privileged" and "superuser" accounts need to stop. This is not good security, this is not zero trust. Either you don't trust anybody and enforce explicit privilege escalation for specific things, or just accept that you're using a "super" paradigm and once you've got access to that user all bets are off.