First Rule of Firearms Safety

All firearms are always treated as if they are loaded.

If you encounter a firearm, you should consider it loaded and treat it as such until you have personally determined by visual and physical inspection that the firearm is NOT loaded. Then and only then can you consider any firearm to be “safe”.

Consistent application of this rule is absolutely fundamental. Consider the following example: You see a semi-automatic pistol resting on a table. The slide is closed and a magazine is in place. There is no possible way to determine if the pistol is loaded or not without additional inspection.
You should always verify for yourself whether or not the pistol is loaded. DO NOT trust another’s word on the status of the firearm. There are countless examples of tragedies that have occurred because someone said “the gun isn’t loaded” and yet it was.