Not true. JK has stressed that not even her husband knew about the plots. In fact she said she chose to keep Arthur alive in order to keep Ron immature and happy-go-lucky and serve as humour relief for the Trio.
No but imagine James walking in later that night and being disgusted because not only did they leave him in the woods but 'you thought that thing was me? I'm much more majestic as that.' And James is forever offended that they can't recognize him.