Always use a holster

Take a look at this article.

I want to comment on the fact that the pistol was unholstered in the back pack. This is the reason that you should ALWAYS use a holster when you carry a gun. A holster does two things, it keeps your gun clean and safe form foreign debris and it keep the trigger covered. If nothing can catch on the trigger then the gun cannot be accidentally shot.

One additional thing to remember, particularly in this example, is that if you carry a revolver the holster should cover the hammer so that the hammer cannot be pulled back while in the holster. Yes, modern firearms do have a safety mechanism that prevents a gun form shooting without pulling the trigger but you ALWAYS need to carry safely.