: 
 :  No, you should never re-instate anything that someone has deleted from their talk page. There's a small exception in the case of a open request for a block review, which should not be deleted. But otherwise, the assumumption is that an editor has read warnings when they delete them, and putting them back serves no purpose other than to annoy the editor - after all, the warnings are clearly visible in the talk page history. Hope that helps.