This doesn't actually work very well, the letters become visible almost immediately, not after hours. And after a couple of hours the whole thing gets black blobs because of the damaged skin. The bananas will probably not get sold and instead thrown away. Don't waste food ever.
They won't stop you at Walmart, though. Not paid enough, plus you can only do "aggressive hospitality." Which is basically just asking if you can help them find anything. Just continue fucking with the produce; they can't stop you.
Putting your stupid comment aside consider all of the resources and time and effort and greenhouse gas emissions that went into growing and shipping that food around the world.