Why did you ask the question if you have already made up your mind. But for those who think your position is sounds, I respond as follows:
1) I'm a good driver too (clean record, no points), but I just had a nice fender bender in Canada. Fortunately our friends north of the border are far more civilized when it comes to handling accidents than we are in the US (or for that matter, Mexico). So it can happen to you anytime, any road conditions, when you least expect it, no matter what your record. In fact, the odds are that you will be in an accident at some point so if you haven't had one yet then you are overdue.
2) You didn't provide the particulars about your wonderful prison experience in Mexico, but I know someone who is currently serving a drug sentence in a Mexican jail -- and I would definitely pay $15 a day to insure that I don't join him. Aside from the risk of jail, Mexican auto insurance typically provides the services of a lawyer - which may prove very useful if you get into an accident.
3) (a) Here in California, you can buy insurance on either side of the border for roughly $10-15 per day.
It is money well spent, as virtually all U.S. auto insurance policies do not provide coverage in Mexico (though they do in Candad). That's right - zero coverage. Check your policy. So you will be driving naked in Mexico if you don't buy coverage.
4) There is plenty of adventure and excitement in life. Risking jail time in Mexico plus potentially $$ thousands in liability exposure when you could have avoided it by buying a $15 policy is just plain stupid.
5) Are insurance and liability laws suspended at night?
