My wife went and visited her father, who has an implanted defibrillator, and they drove around bunches with him in the front seats and there was no issues. She even called him after I read this to her and they had a good laugh about it...

He is not worried about this issue and I don't think you should be either.

{sarcasm} Now the doctor did say that they were going to disable the defibrillator when he gets his next colonoscopy. Maybe we should worry about defibrillator owners causing damage to our FEH if they activate. {/sarcasm}