What can I do to encourage my dad to wear his personal emergency response (PERS) device?

A fellow caregiver asked...

My dad, who has heart disease and a history of strokes, simply refuses to wear his personal emergency response system (PERS) device. We've tried all kinds -- a pendant, bracelet, even a belt clip -- but he says they're all uncomfortable. I've paid for the service and am anxious to know it's helping to protect him, so how can I get him past this resistance?