Greg, I haven't looked at Glocks lately and I remember them as not having an external safety or hammer like a Colt 1911.
Which they called the safe action trigger system.
From their site:
This safety can only be released by the trigger being pulled by the trigger finger. It automatically re-engages after the trigger is released.
I prefer a manual safety.
That being said, I carried my G-23 with a round in the chamber and a holster that enclosed the trigger guard completely.
The only real safety it had was keeping your finger out of the trigger guard till you were ready to shoot.
If you are surprised by an assailant and fear for your life, there may not be enough time to chamber a round and then shoot.
Allen