1) Maybe there are official rules about drawing that are very clear in Korea and I'm just not aware of them.
2) This doesn't come up very often. Games that get into the territory where things become extremely tedious and draw rules might be necessary are rare. Professional games that are actually ruled as drawn, though there have been a couple, are even rarer.
It just seems like a fundamental flaw with the game, if only a small one, and since this game is so good otherwise I wish someone would fix it. To explain the flaw, sometimes a game reaches what is effectively a stalemate. This is when it is literally impossible for either player to eliminate the other's last building. When this happens, or comes close to happening, I certainly get very excited because it is such a strange occurrence in StarCraft, and I'm sure lots of other people get excited too. But after 10 minutes or so of the game stretching on with absolutely nothing happening, it becomes a problem, not just for the spectators, but even for the players themselves. Sometimes the game is technically winnable, but just very difficult for both players to make progress without taking a disproportionate risk. Other times both players may feel confident that they can still win, but are overindulgent in taking their time towards activating their plan.
Some of you may be aware that this is something that comes up much more frequently in the game of chess. In chess, there is a long, time-honoured tradition of long boring games that go nowhere, and they have a number of very clear and simple rules to help players, and tournament organizers navigate those waters. In chess the conditions for a draw are simple:
1) If one player offers a draw, at any time during the game, and the other player accepts.
2) If it is logically impossible for either player to win, because they lack the necessary in-game resources to meet the win conditions. In the context of chess, the necessary resources for winning are very well understood by chess theorists, so this rule is completely explicit and can be applied by simple reference to a manual, if necessary.
3) If at any point in time, play has continued for a certain period of time without certain official markers of definite progress being met. In the case of chess, a game is ruled a draw after 50 moves have gone by without either player moving a pawn, or capturing a piece. This helps tremendously with ruling over the gray area where the game simply becomes very boring, while still technically being winnable, without the rules needing to be arbitrary in order to deal with it.
My suggestion is that StarCraft should implement a slightly modified version of at least some of these rules, so that when this does happen, it isn't as confusing or lame or torturous to everybody involved. It is also just as important, in my opinion, if for no reason other than a matter of principle, that the process by which a game is ruled a draw is completely non-arbitrary. The whims of sports referees are often defended by fans for their ability to inject a "human" element into the ruling of the game. This results in games like soccer having a very different time-honoured tradition, namely riots. In my opinion it is better that things are as objective as possible, which usually means being explicitly set in stone as much as possible.
So here's my rough idea. Suggestions and refinements to this idea, as well as a wholesale rejection of all of my stated premises, are welcome. A game of StarCraft should be automatically ruled a draw:
1) If both players have buildings which are inaccessible to each other's standing army, and no possible access to resources which would allow them to make an army capable of destroying each others' buildings.
2) [edited] If at any time during the game, 3 minutes go by without either player producing or damaging any unit or building, a draw will result, assuming that both players have either the capability to win, or the capability to defend themselves. If only one player can win, and the other can neither win nor defend himself, then the player who can win will be awarded the win automatically.