Although it may be chat spam, it is not much of a concern considering the chat will be spammed yes, But if spammed, just politely request them to stop. I doubt Death himself would add to one of our pluggins to prevent a lenny face, and I don't think a timer is available for chat messages given.
But I suggest if a player or players are going overboard with it, ask them nicely to stop, and if that does not work, report to an Admin for your concern. Personally, I don't see this to be a problem if used minimally, But if it's spammed on a mass scale, then Administration actions might be Required.
