I hope no one noticed.

[Floater]

Yes, I sometimes forget to lower the scope when surfacing, and only notice it in external or bridge views.

The USN often cruised on the surface with a raised scope; the Kriegsmarine doctrines explicitly forbade the technique on the grounds that it could be seen from further away, which I think was a mistake. After all, a periscope is a lot thinner than a ship, and the USN certainly found the technique useful.

There's a picture in Robert Stern's Type VII U-boats (p.66) which shows a partially-raised scope with a crew member strapped to the head. The guy's using binoculars. That's the only reference I know of to a U-boat having its scope up on the surface.