I meant as being unreliable in relation to lock screen i.e unwanted access to a machine.
We had a similar thread a while ago and eventually opted for "i3lock".
That way you would lose your session and maybe your work.
Gave it the option to start "xscreensaver" and the lock the session, you will have to install "xscreensaver" first for it to work.
This will still leave your ttys accessible, though but doesn't have the strange bug "dm-tool" has.
Be aware though that it will keep xscreensaver running until you manually exit it with "xscreensaver-command -exit"
So actually it has now become a choice showcase: either i3lock or xscreensaver. …