it would appear to me the crown/blade guard is not the fault in your cut but the fence is the problem. Many of the american style fences fault the crown guard in narrow strip ripping. What is called for in narrow strip ripping is a low position fence. Its a shame that the Americans answer to narrow strip ripping is with the Grr ripper and by its very nature removes the blade guard instead of make a good high low sliding rip fence plate fence. They have adopted the riving knife so there may be hope yet. I do see that in OHS does recommend the sliding fixture to hold the piece so the fence does not upset the crown as some has said is a safe way to cut small work but this does not deal with long pieces. If the GRR ripper is suddenly removed ask yourself where is your hand?