Some additional info:
In order for the watchdog to actually lock out your machine, you'll need "lock" privileges. You can determine if you have lock privileges by doing a
qbusers --list
total 4
---- jcg krmpbuicseyqg- default
asil jcg krmpbuicseyqgp Administrator
asil jcg krmpbuicseyqgp qube
asil jcg krmpbuicseyqgp root
asil jcg krmpbuicseyqgp system
and looking for an "l" in the line next to your name, or an "l" next to the default user.
If you want to add lock privileges for yourself, the command would be:
qbusers --add --all --lock myname
To add it for the default user:
qbusers --add --lock default
You will need to be an qube admin user ("a") in order to add users or modify permissions.