There's a lot of unwarranted paranoia about this. Simply apply for the visa, do not mention Tibet on the form, and see what happens. Obviously don't book any expensive tickets etc until you have the visa in your passport, but I suspect no major problems in reality.

As others on here have said, once you have the visa then you don't have any worries at the airport. The whole point of the visa process is to avoid problems on arrival in China (though I would argue the biggest point of all is to make money).

There are serious overestimates here as to how far China is even remotely bothered about screening visa applications on pure political grounds. Clearly, if the OP has had a leadership role in pro-Tibet organisations, runs anti-China websites/Facebook pages, or done something like play a concert in Hyde Park in favour of the Dalai Lama, then there is a risk of rejection, but marching down Whitehall or Trafalgar Square with a few hundred others, or even demonstrating across the street from the Embassy, is highly highly unlikely to raise any issue at all.

The problems only really start if the OP actually starts causing trouble on the ground here. Unfurling a banner in Tianenmen Square or similar really would lead to them being blacklisted, as would associating with known dissidents in many cases.

To give an example, in 2008 the UK band Oasis got visas to come to Shanghai to play a stadium concert despite having played at Free Tibet events in Europe in the past. The visas only got withdrawn after local newspapers uncovered evidence, making officials uncomfortable.