...the "misspell it as 'tianamen'" trick described by someone (Greg?) here last week.
For another, they've already been doing that, but the other way, for years: I've had immense problems getting it to respect my bookmark to the Advanced Search page; it used to redirect to google.fi every fucking time. (Which was driving me insane[*]; I much prefer English to Finnish.)
Lastly, though, to sum up: If the way it works is that people in China can't see this stuff at all -- and presumably don't get redirected to google.com -- then, from a pure "better search" point of view, they're just trying to do you a favour by redirecting you if possible (i.e, if you're not in China).
Sure, that can also be seen as trying to cover up the lack of search results the Chinese get, from us Westerners... But not exclusively so, AFAICS. A bit more grey, not just black-and-white.
[*]: OK, OK: Driving me even more insane.