The present situation in China is the following from what I understand.

They do selectively block certain Web sites including EarthWaves. However, in most cases, E-mail reports can be exchanged with researchers in China without any problems.

It is not actually illegal to forecast earthquakes there. Instead, in certain parts of China it can be illegal to circulate an earthquake forecast in public. But if you are working on that type of technology you can freely send forecast information to government officials who might try to work with it. Or they might simply choose to ignore it.

Outside of China it can be difficult of impossible to send those same government officials any forecast data. For one thing there is the language barrier. I am guessing that unlike Japan and India, most China government officials don’t know how to speak or read English.

In the U.S., earthquake predictions are “protected speech” under the First Amendment to the Constitution. However, that probably does not mean that a person can be totally irresponsible with his or her forecasts and deliberately try to frighten people out of their wits.