Grumbler, grammatically correct, but not something anyone would say in this context. I'M SURE YOU'VE DONE THIS ACCIDENTALLY would be better suited for mistakes one makes at some point over the course of their life: "Locked out of your own house? I'm sure we've all (accidentally) done this /(by) accident(ally)." When referring to a specific, single act, it's better to use the plain past: "I'm sure you did this by accident." ACCIDENTALLY sounds better in front of a verb phrase: "I accidentally locked myself out of the house." -but- "I locked myself out of the house by accident."

Also, putting PLEASE after the request changes the tone completely. We usually use it when we remind our kids to do what they're supposed to: "Wash your hands, please." So when we use it with adults, it sounds a little condescending: "Tatiana, your break is over - turn off the coffeemaker, please." (<-- I'm surprised I have to remind you). Putting PLEASE first makes it cordial and sincere: "Tatiana, please turn off the coffeemaker." (<-- I forgot to turn it off, would you kindly do it for me?)

DON'T WORRY isn't the most natural expression here, but if you insist (all of you) on using it, at least add ABOUT IT.