With the Fall Update, Microsoft has introduced a hybrid locking mechanism that effectively harms the first method [ for swapping game saves] and squelches the second method. Method 1 has been smacked silly because the vast majority of existing game save files created on the previous update do not work on the Fall update software version. This renders those files useless until unscrupulous members decide to re-upload hundreds of saves based from the new dashboard version. This will most likely take months upon months or possibly never happen for very unpopular games.
Method 2 has been rendered useless as new console specific security is in place. Gamerscore thirsty gamers are taunted with a Corrupt Save message when the bypass method attempts to be used. Obviously, the new security may eventually be cracked by code junkies, but those game saves may also have to be re-uploaded. I'm unsure of any repercussions to method 3. I've always found trading accounts to be supremely idiotic as anyone could keep your account for themselves. Anyway, if anyone has heard if method 3 has been affected, let me know.
Former champ ST TheKing quit the GamerScore race after the upper reaches of the leaderboard became became clogged with fakes, including awfullygood himself (who admits he was cheating just to keep up with the Joneses). Sure Xbox 360 achievements are intangible and useless, but they are fun to earn and these a-hole cheats make a mockery of every pallid kid who spent a three day weekend in the basement going after that final Lumines Live time attack get. For God's sake, if putting endless hours into a crap game like Bomberman gives you a limited sense of accomplishment, stealing a game save must give you even less. Of course, these changes won't stop cheating, just slow it down for a bit. But it does serve as a reminder that you're not entitled to an elite score, unless you're playing that other console.