This question already has an answer here:
I am running a single-user Ubuntu install.
When I enter the password to unlock my screen after suspend/timeout, it is the same password I use for
sudo - my user password. Is there any way for me to set a different, weaker password for unlocking from sleep, so it's safe to give it to friends that, for example, are reading something on my computer and forget to wiggle the mouse without me having to give them potential root access if they decided to?
The only reason I even have a lock screen is so little siblings won't hit random keys and mess up my work when I forget and leave for a minute, so lockscreen "security" is totally a non-issue.
I am using GDM / Gnome 3.16 on Ubuntu 15.04.
I need to add that removing my login account from sudoers and using another account for sudo-related work is not a solution that I can consider.