Almost always, but there are times when I can't even find a cart corral and am far from the store. In those cases, I at least make the effort to put the cart out of cars' way and so it won't roll.
I got into a real argument with a woman who wanted to leave her cart in the empty parking space next to her - the one I was trying to pull into! I waited while she loaded the groceries into her SUV - it's not like she didn't know I was there. I wasn't even asking her to put the cart in the nearby corral, just up at the front of the space so I could pull in. She called me all kinds of names.