Prepare to have your mind blown

[Alerith]

I wouldn't be so sure, multiple times using the echo has shown that we have a physical presense in that part of the past when we use the echo.

Right, but I think the debate is whether or not your presence in the echo affects events outside the echo.

Say I use the Echo to view your past, and I eat your cake in the Echo. When we return to normal time, did I really eat your cake, or did you still eat it and events were never changed?