This is between Dallas and Denton Texas. We are over run with traffic etc. It is no wonder that all the small communities along I-35E have laws pertaning to RV parking.
The Walmart workers do not say anything but signs are posted by the city. You park and wake up with a ticket on your windshield.
We live here on Lake Lewisville. We have no less than 5 great camps on this side of the lake and many people use the Walmart for last minute supplies. When someone arrives too late to enter the parks (10PM), they sleep on the Walmart parking lot. If it is a slow night for the patrols, they awake with a traffic fine. CAUTION