This happened to me once during a product launch — a draft presentation ended up in a client’s inbox by mistake. To prevent it from happening again, we created separate internal and external folders with clearly marked permissions. Before sharing, we double-checked the folder type. I came across a similar method on
https://ejoi2018.org/, which recommended adding access logs so you can see exactly who opened a file and when. That extra step not only stops mistakes but also builds confidence that sensitive files are handled correctly. We haven’t had a single wrong-share incident since.