My loan company (Wells Fargo) and my husband's (Compass Bank) both have a ten day grace period. I would imagine on the 11th day, the bank(s) would start calling us. We have never been late on our payments, so I do not know how that works. We are responsible and pay our bills on time. My husband overpays his car payment by $50 to $100, depends how much extra money we have. My car payment is only paid an extra $10 or $20 per month.
Not sure about that GPS installed on her car though. That would really piss me off. I do have a GPS unit in my car, but that's for my personal use. Not for the bank to use to try and intimidate me. I'd have my husband find it and immediately uninstall it. Then I would return it to the dealership or bank and say, "nice try, now have a wonderful day"
I am not okay with people being tracked because they are "high risk". It's just not cool. I'm sorry.