While I agree with DaRock on the benefits of the cross bracing, I've both the WM and Nitroplanes versions of these planes ( at least two of each ).

I've had one of my NP Ultimate 40s cartwheel end over end very violently on the airfield w/o any apparent damage... ( other pilots were quite impressed with the plane as a result... )

Then I flew the plane all day... performing many high G stunts...

The next day I discovered that one of the interplane struts had broken off after the cartwheel incident, and I had been flying with ONLY the carbane and the remaining strut holding the wings together. They are stronger than they look!

Bottom line, yes you CAN do as he said, but as I discovered it's not NEEDED with the NP version.. but it never-the-less may be a good idea.

BTW. the NP version has a thicker metal center carbane assembly so this may have something to do with it too.
I also only had one screw per leg holding the carbane to the fuse.