Reading between the lines, I sense that Lawoftheland is looking for a stick with which to beat owners (for the very good reason that security and safety are being compromised).
I would think, if nothing else, doors left open constitute a fire risk as well as an open invitation to thieves.
I would be tempted to put up a by-law making it a specific offence to leave these doors open, then launch and education campaign letting people know they could be fined for doing so and if that didn’t work, start making noises about installing security cameras.
Most people will probably get the message before you actually do that.