Eat Street Gate - Tuesday Nights

Last Tuesday, the gate to the Eat Street Carpark was left open again.
This is something that happens too often as the last people to leave the site are always out the front and therefore forget to lock it.

Other than telling people to make sure they check it and lock it before they leave, I was hoping people may have some ideas (hey we can try innovation) on how we could improve in this area.
Maybe a better way for people to checklist off the site.
Maybe some sort of reminder.
Open to suggestions.

A few months back I proposed getting some Xiaomi Aqara door sensors for tracking internal doors. This could potentially be placed in a waterproof casing on the gate to track this, with a visible light on inside the greenroom when that gate is open?

I have mentioned at meetings having a “last person out” rfid swipe, this can confirm doors close, send a notification if not. Maybe have a display inside showing what is open and what is not - using @nogthree 's door sensors…