Several years ago they did. But then spillover from the homeless problems (as seen in Seattle) caused homeless to park on private property like Wal-mart's. The crime rate went way up and I'd see broken window glass all too often. After overnights were disallowed by posted signs, there were no more broken windows. Someone started tearing down the no overnight parking signs on the east side of the parking lot, such that the last sign remaining is at the northeast corner. The walmartlocator.com site lists wal-mart's that don't allow overnight parking.
Not on a regular basis.
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