[coldblues]

Anyone who is using full disk encryption will be turning off their computer when they're not around. Hibernation is an option if you want to keep your state.

[lgeorget]

I was about to comment that exactly. If you computer is never switched off, your encryption is permanently bypassed.

[bluebarbet]

True but in practice it's still worth something if a screen lock is used. The police won't be foiled but a casual thief is likely to unplug or reboot and at that point your data is protected.

[charcircuit]

Unless you use iOS which properly handles clearing encryption keys when the device is locked.