Where reusable bags are still allowed, you may see the cashier refuse packing your groceries for you. Don't blame them if they do, they're essential workers and staying clean is key. Meanwhile, reusable bags simply aren't clean unless you make sure they are between visits to the store. And some chains, like Wegman's, gave managers the right to deny entry to a shopper with a dirty bags.
Keep in mind, the coronavirus can survive on cloth for 2 days and on polypropylene for 3 days. And if that doesn't get you cautious, E. coli, salmonella and norovirus can also be found on bags that aren't clean. So if you still want to take a reusable bag with you, cleaning it between uses is essential. For cloth bags throwing them in the wash will do it, for plastic-based bags dish soap is enough.