I’m not going to suggest that you not lock your doors. I read in the papers about thefts taking place all the time. While riding up top on a nearby mountain where radio towers that take handle everything from police, fire, internet and phone I found that most of the gates protecting these expensive facilities were either open or almost locked. See image below.
The seems to be the general attitude of most things. These towers are so remote that if you wanted to simply cut the chains with a very loud saw, nobody would know. So, I guess they simply don’t worry too much about it and trust people. I like that.