In my area the beer sales on Memorial Day are prohibited at liquor stores however you can still buy the beer from a Grocery Store on Memorial Day.
But that doesn't make sense because it shouldn't matter where you buy the beer from on Memorial Day and if they're gonna ban the sale of the beer on Memorial Day through Liquor Stores they should also ban the sale of the beer through Grocery Stores.
So if you want to buy beer for Memorial Day you should buy it either before Memorial Day or may have to go to a Grocery Store to get the beer.
I drink some beer on Memorial Day myself and just go to the local Liquor Store a few days before and buy the beer then.