I looked into that insurance last year for our daughters car. Decided to pass on it though.
it made too much sense for me. as long as i have 90 days of consecutive storage in a year, it cuts my insurance on the car by half.
Normally it is very easy for the car to be garaged for December, January and February in Pittsburgh. just sucks on those rare 60 degree days in december or january and you are having boost withdrawal. haha