I grew up in a city that had around 20,000 people in it; it’s up to over 60,000 now due to annexing. My father had a wise saying “Locks are for honest people” and I early on realized the point he was trying to make. A dishonest person will find a way around a locked item. I also learned that keeping keys in a vehicle is a bad idea. Even if it’s locked, it’s pretty easy to break into a vehicle. I bring this up after seeing a local TV channel where someone left the keys in their vehicle and the vehicle was stolen – https://www.ksn.com/news/crime/one-dead-one-injured-after-car-crashes-into-church-in-east-wichita/. I routinely see vehicles with keys in them at gas stations, including keeping the vehicle running while gassing up, another bad idea.
I lived in several small towns years later where the locals kept the keys in their vehicles. I never did that as it’s too easy to steal a vehicle with the keys in it. I was probably one of the few in those towns who didn’t keep keys in my vehicle.
It’s your choice to keep keys in your vehicles, but considering the ease of taking a car with keys in it, I wouldn’t advise to do so. I figure why encourage someone to steal a vehicle by leaving the keys in it.