i just checked it again and still easily worked around with ctrl+alt+f7. in addition it also now seems to break my touchpad.
i've found it to work across all DE's and DM's so far and never fails to work properly. you can use xautolock to have it lock after a certain amount of inactivity. if you want it to lock on suspend i have a service i wrote for that.
(you can replace blurlock with i3lock if you want)
i have this autorun at boot to set an inactivity lock.
xautolock -locker blurlock -time 5 -resetsaver -detectsleep
heres the lock on suspend service
sudo nano /email@example.com
(replace @dglt with your username @username)
#sudo systemctl enable firstname.lastname@example.org
Description=Turning blurlock on before sleep/suspend
sudo systemctl enable email@example.com
sudo systemctl daemon-reload
modify to your needs, i just prefer blurlock instead of plain i3lock. dont forget to replace @dglt with your user name so the the service works properly.