And now ask yourself a question why would they want to do that? I mean why keep unneeded load on their servers and support whole infrastructure just to forward

And now ask yourself a question why would they want to do that? I mean why keep unneeded load on their servers and support whole infrastructure just to forward e-mail. Probably because they want to continue to reading your e-mails but now they don't have to invest into storage. Just copy the interesting ones for themselves.