I'm pretty sure there was a movie about such a situation from probably 20 years ago, maybe more.
I suppose it makes sense that if you're going to hole up for a while, do it in a place with all the supplies and plenty of spots to hide, and where being in there 24 hours a day is not an issue...
Probably only walmart meets those criteria in the area.
"Home is where the heart is" starring Natalie Portman.