Any suggestion to watch Jeopardy on a particular night could only mean one thing, really. I saw a spoiler on Twitter in the middle of the day that kind of ticked me off, but I wouldn't have been watching it anyway (only see it when it's on in the background somewhere).
He's obviously a very knowledgeable guy, but the thing that I thought was amazing was that nobody else had every thought of starting from the high-value questions before. If you get most of those and leave the other contestants with the pickings, you're almost assured of winning.
And yes, Alex Trebek is the second most cherished Canadian (behind The Great One), and I hope he beats the C and hosts for another 20 years.
Other people must have used the same strategy as there is a name for it (I don't remember it though). The Jeopardy people don't like it as it disrupts the flow of the categories where the questions start easy and get more difficult as the money increases. However, there are no rules against what he did.