I saw a guy on YouTube test like 6 different webcam covers and he said the sliding ones are the worst for this exact reason. He timed himself and forgot to open it something like 4 out of 10 meetings. The ones that flip up on a hinge were better because your finger hits them when you go to close the lid. But honestly any cover you have to remember to move is gonna fail sometimes. My trick is I put a tiny piece of red tape on the edge of my screen so I see it in my own camera view. If I can see red, I know the cover is still closed. Sounds dumb but it works.