What is 'evidence'?
Given that the point of evidence is 'that which is evident' or plain to see, I really don't see how any material can be submitted 'under seal' (or which cannot be seen by the defendant etc - see recent UK gov plans for secret trials and convictions etc). If either party wants to present something is evidnce then it has to be published for all to see or it ain't evidence. It's not a difficult concept to grasp, although it does seem to elude certain politicians and judges.