Let the foreign press have unlimited access. If the Tibetans are doing what you say, then give them enough rope to hang themselves (so to speak).
My impression is that the West will side with Tibet regardless of whether China's allegations are true. In fact, I've seen multiple sources that acquit the Tibetans because "when nothing else works, violence is the only answer for a desperate people." If foreign press was allowed unlimited access, this outlet will be given free reign, and it'd set a precedent for other groups to adopt similar tactics so that they could get similar coverage from Western press - bad news for China.
It's always the press's fault.
Chinese man convicted for 10 years in jail for divulging "state secrets". He was a journalist who published a message from the Chinese government warning against reporting on the 15th 'anniversary' of the Tiananmen Square Massacre. That's it; that was the state secret:
http://www.rsf.org/article.php3?id_article=14884
Chinese man sentenced to 5 years in prison for rallying public support of the message "We want human rights not the Olympics". Reason: subversion of state power:
http://www.thestar.com/News/World/article/350435
It's a shame China doesn't have a proper legal system with things like due process.