The official product manual that I downloaded from Beretta website a minute ago says:
"IF YOU ARE NOT READY TO FIRE
Engage the thumb safety by rotating the safety lever with a fully upward thumb pressure, so as to cover the red warning dot (the red dot is visible when the thumb safety is disengaged), causing the hammer to decock and rest on the hammer stop."
And in red font:
"WARNING: Always ensure that the safety is fully engaged until ready to fire. A safety is fully engaged only when the safety can move no further into the safe position. A safety which is not fully engaged will not prevent weapon discharge."
I seem to recall that some other guns had additional behaviors when users tried to lifehack their safeties by placing them into unintended positions (IIRC Ruger Mark IV was one). If these overly smart shooters were successful, it usually ended in a recall.