By the rest of the story I’m talking common courtesy, such as asking them to leave before being booted.
Now Walmart may have tried that then Trucker’s became belligerent causing Walmart to just boot and tow, that could be the rest of the story.
So you want Walmart workers to make hourly trips to the parking lots and bang on trucks asking them to move? That’s really stupid. That’s why they put up a sign.