Heard a guy at my kid's bake sale say 'just use the recipe on the box, nobody can tell' and I need to say something | Baking Fails And Wins - Pinecone Attack
The real issue is what your kid learns watching you stay quiet. That guy just told a room full of kids that cutting corners is fine as long as nobody catches you, and half of them probably heard it. Next thing you know your daughter is asking why she has to try on her science project when "nobody can tell" if you just copy something off the internet. You do not have to make a scene, but a simple "we actually made ours from scratch, it was fun" said loud enough for him to hear does the job. Kids pick up way more from what we let slide than from any lecture.