I've just tried it and I get signal from both the output and the send.Have you run it that way (or seen someone run it that way)? I don't see an example in the manual, and would assume that going out of the send, without ever coming back into the return, would...leave you with nothing on the balanced output. But perhaps my assumption is wrong.
It does say it in the manual but the diagram refers to adding additional effects and using a splitter box.
So it depends on your setup - but technically you can run both.