2017~2021 Rear hatch opening by itself?

[sm1ke]

My point is that there should be some way of turning the auto lift gate on or off.

I see, that point wasn't clear.
I'm not aware of any manufacturer that has that option on their keyfobs, so even if you never buy a Mazda again, you still wouldn't have a solution to your problem.
I suppose you could try removing the button from the keyfob to disable it? Certainly wouldn't be as easy as a simple lock switch though.

 

[Sig cx-5]

I have 2017 CX-5. The car was I. The garage with the garage door down. Car was locked. I went to open the garage door from the outside and the door stopped going up. The door stopped going up and jammed. I then opened the other garage door went into the garage to see that the Mazda lift gate opened against the opening door and bent the bottom of the lift gate. The fob must have come into contact with something else in my pocket and opened with out me knowing when I went to open the door from the outside. Went to my Mazda dealer and they could care less. Had no answers for me. Haven’t gotten it fixed yet, $700 to $800 to fix. I wouldn’t buy another Mazda.

Haha! You should probably also avoid Honda. They have a "feature" that opens your windows and sunroof by pressing something on the fob. There are many complaints on the CR-V forum about this. There is no way to disable it, either.

 

[TBarney]

Useless. Took it off. Doesn’t prevent accidental button presses at all. In fact, makes them more likely. Sigh.

What kind did you get? I'm wondering if one of these "leather" covers made for the Mazda 3 (without hatch button) would help:
3 Buttons Protection Key Case Keychain

 

[GAXIBM]

I found a video showing how to change the fob battery in my 2020 and took it one step further to reach the plastic spindle on the back of the tailgate open fob button and cut it off. Problem solved, I never used the fob to open the tailgate anyway.

 

[Davidiot]

What kind did you get? I'm wondering if one of these "leather" covers made for the Mazda 3 (without hatch button) would help:
3 Buttons Protection Key Case Keychain

These: