Bots don't have code to check for that?  From what I've seen the same could be said of damage shields.  I group with a druid and wizard atm and they don't repeatedly cast DSes trying to overwrite each other.  Same whn I had druid mage bots grouped.  I'll check it later and add a shaman to my group and see what happens. 
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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