These carts have, for the last couple years (I don't remember when, exactly), the locks on the front left wheel. It can't be to "disable the carts if someone tries to take them out of the parking lot". That isn't an issue. Though I have not seen it in action, I suspect that if I tried to take a cart through the exit without somehow moving it past whatever device deactivates the lock would have the cart lock up and start skidding (though with the lock being on the front, anyone should be able to just pop a wheely with their body weight and keep on trucking).
That said, I don't claim that these are effective at loss-prevention, but sometimes those jackasses get crazy ideas in their heads and won't be dissuaded by common sense and reality and all those other naive things.
A grocery store at Bayview Village, an upscale mall in Toronto, uses this system to stop cart travel outside the grocery store parking garage. Mall management considers carts trashy and that they otherwise bring down the appearance of the mall. This was one of the conditions when the store opened in 2005. Their cart policy may have changed 20 years since.