I recently learned how to operate those things. They are not a toy. However, I did not see a sticker on it stating "DANGER - UNIT CAN BE DEADLY" Maybe they should pick a little sticker on it.
A few (repeat: few)of the people I've seen working as EMTs, I wonder how they ever made it out of high school.
You most likely received training on an AED, an Automated External Defibrillator.
What this guy used was a non-automated defibrillator that Paramedics and some EMT's use.
An AED will not deliver a shock unless it has analyzed a patient and found them to be in need of a shock (in V-tach or V-fib). You can't just hit the button.
AED's are very very safe. There is no need for a sticker
I don't have a sticker on my car warning me that it can be deadly.
Don't use one on me unless I am actually in fib. I have a pace maker and these things will zap it and cause heart failure(cardiac arrest). Even a person with a normal heart can suffer cardiac arrest when zapped, they interrupt the electrical pulses of the heart, then the heart can reset itself, that is if the heart was beating abnormally, if not it can cause serious consequences, such as death! I find it strange that I know this and a person trained to use them doesn't know it.