Sinking ships in port

Harbor-Raiding...uhg!

I don't see any moral issues whatsoever with sinking ships anchored at port. As long as they are bearing enemy flag in wartime in disputed territory, that makes them active participants and thus fair game according to every rule of engagement known to mankind.

Perhaps in WW2 history it didn't happen so often because of the tactical disadvantages (even pre-MAD) involved for a sub to be in shallow coastal waters. Alternatively, I cannot think of any tactical advantages in waiting until freighters leave port with DD escorts to start sinking them. Hell, sink the DD's at port FIRST and come back later for the freighters...