Walmart's masks-required policy goes into effect today, I believe. Lowes and Home Depot have also announced masks to be required. If you wanted to pick a venue almost guaranteed to out the no-mask opponents, you couldn't do much better than Walmart, Lowes, & Home Depot.
There have already been some gun-waving incidents in Wallyworld last week when customers were asked to put on a mask. I'm expecting quite a few more as it becomes policy. My news feeds say that the Walmart employees are scared to try and enforce it.
Home Depot says they are putting bouncers at the entrances.