Oogle,
Last summer an AUA DH8D advised me to have left engin problem and wanted to divert. It took me some time, in very very busy afternoon, to find out that he was declaring emergency. And that happened only after I've asked him "Are you declaring emergency?" He sounded like he was not shured whether he should do it or not, but finaly said yes. The point is, I cannot know unless I'm told. How can I recognize that anyone is in problem? I can only assume and assumption can, and usually does, lead to mistake or misjudgment. What ever you need or have to say, say it! Do not expect me to read anybodys mind. I am sorry but I can't do it. I am neither trained to do it nor I have the powers of my own. However, if I'm told either Mayday or Pan, I know precisely what the procedure is, and what must be done, and, what is even more important, I haven't met a single controller that wouldn't do much more than requried by the book.