AIO for telling my wife she shouldn’t put soda in the ketchup cups?

My wife and our three kids were at a local burger joint grabbing a bite. We each got a burger, and some fries to share, but didn’t get any drinks because we don’t need soda, right? And of course, our youngest, who’s almost two, is being antsy because that’s what two year olds do. And to settle him down, my wife grabs two of those little cups you put ketchup in for fries, fills them with soda from the drink machine, and gives them to him. My immediate reaction is to just ask what she’s doing, and why she’d do that when we didn’t pay for it. And of course she tells me I’m overreacting and that it’s just a couple drops, but it’s the principle of the thing! And like, I know it’s not that deep, but come on lmao. It just seemed like such a cheeky thing to do, especially in front of the two older, impressionable kids! (They’re 4 and 6.) Anyway, what’re we thinking? Straight to divorce?