Have you ever found yourself staring at an email and trying to decide whether it's appropriate NOT to reply? These decisions can take awhile. Does he expect an answer? Will he be offended if I don't answer? If I DO answer, will he feel obliged to answer again?
I have no easy solution to this problem for myself, but I try to solve it for others. It's a pity that "NNTRTTI" isn't a well-known acronym. Instead I spell it out, wherever I can: "No need to respond to this item."