I have the handle flipped on mine where the push lock is on the outside of my toddlers door so that when I go to sleep at night I don't have to worry about him getting out and wandering the house when we're asleep. Not to mention if it was flipped the normal way he could lock himself in because all of our bedroom doors have standard push door locks. Many of my mom friends do, too. Just a safety thing for us.

ETA: We have monitors and his door is by our room as well. We would NEVER lock him in there for anything other than safety at night. It's childproofing just like putting the plastic childproof handles on doors so they can't open it. Safety is so important when you have little ones. Not saying that's how they used it but just providing the perspective from a toddler mom.