We were on a road trip and got to a motel late at night. My wife was grabbing some stuff from back seat on other side of CX-5. We were exhausted from long day and she mistakenly left the back door wide open. I did not notice that from my side and locked the car and went into room. Luckily my wife went out for a smoke and saw the door was open.

I could not believe that the CX-5 would allow me to lock it with a door open and not provide some sort of warning. The indicators for the door being open on dash work showing there is a door open. Yet I can lock the car with it wide open.

Is that normal?

 

You can "lock" the vehicle with any door open.
But when you do that, it will automatically unlock all the doors, except the liftgate.

From the owners manual.

• The vehicle lock-out prevention feature prevents you from locking yourself out of the vehicle.
  
  (European models)
  
  All doors and the liftgate will automatically unlock if they are locked using the power door locks with any door open.
  
  If all the doors are closed even though the liftgate is open, all the doors will lock.
  
  (Except European models)
  
  All doors and the liftgate will automatically unlock if they are locked using the power door locks with any door or the liftgate open.
  

 

Thanks for that but should there not be a warning beep that the car is not secure. Had my wife not been a smoker the Mazda would have sat outside the motel with the door wide open all night.

Finally an upside to her smoking habit.

 

Depends on how you set-up your security/lock system in system settings.
I prefer no sounds (beeps or horn), all mine does is flash the lights.