Actually I try to take the keys out of my equipment when it's not being used and especially if I am not around. Not so concerned about actual theft but joy riding. ..."Hey, wouldn't it be funny if we can run this backhoe through the barn or into the neighbours pool" ...you get my drift.
Actually what first caught my attention t was your picture of an exactly-like-mine 430. Maybe not exactly like mine; the sheet metal on yours is less dinged up and a lot less rusty. Good tractor though and easy to work on. The main issue around here is that it's getting hard to get parts for them.