The bolded part is what omits you from the law. Although not on the clock, you still are employed by an EMS agency. (assuming this by your other post)
Any decent lawyer could take you to the cleaner if it did end up in court and you used this Good Sam law as your defense.
Don't take this the wrong way I agree with you about helping people. However, I refuse to risk my livelihood, my certification, me health and possibly my freedom for a complete stranger when I am not on duty and covered under my agencies insurance.
Paramedics tend to get a little more education when it comes to legal/liability subjects.
You are incorrect. The law only applies to those that are WORKING (i.e. ON DUTY) for whatever their service be. Your last thought is correct, we do have a class we have to take on the legalities and this was one thing that we were spoken to about.