I used to be the same but nowadays I'm too busy, half the time my cars are never locked as I forget, must say I've had cossies for 20 years, left them parked up all over like any car, never had an issue, was followed home once but same as others, back roads and a bootful then into the garage no worries.
Have an old 1960's classic sat on the drive that I can't lock I'm more worried about, have a lock up for it but it's not running right and need it at home for now.