I have trained, and trained with, several different US and Foreign Military Elite Units and US and Foreign Swat Police.

Some units that used H&K Weapons did operate with their safetys off at all times.

Those units that used the M-16, M-4, AR-15 type weapons always operated with their safetys on, until the decision to fire was made and the gun was on its way "up".

When I operated with an H&K 33K, or an H&K 91, I "worked" with the safety off, and my finger behind the trigger, until the gun was on its way "UP".

When I used a M4 the safety was on till the gun was on its way "UP".

When hunting, I keep the safety on, or in the case of a Blaser keep the gun uncocked until I have decided to shoot the animal.

When I feel it is proper I take the safety off/cock the gun in preperation for the shot as I raise the gun.

If the shot goes away I make the gun safe.

Whether in combat or in hunting, unsafe gun handling cannot be tolerated.

I really like H&K guns, but many teams have gone away from them because the safety is difficult to operate when in normal ready gun.

If you carry the gun sideways, close to your chest, when the decision to shoot is made, then you take off the safety as you bring the gun "UP".

Bottom line is, you do not want to be shot by the bad guy, or killed by the DG [both I would consider an honorable death], but you sure do not want to be killed by an accidental discharge.

Nor kill some one else by a mistake.

Bottom line is, if you know your gun, are confident in your ability, then you will not be nervous and make a mistake.