Sorry, the idea that the Chinese gov't. would take action against any foreigner (non-Chinese) saying "Fuck China!" or anything else derogatory in one of these cars sounds quite absurd to me. Possible, I suppose, but certainly not likely.
Now for Chinese citizens, that's a whole 'nother story. But really, the idea that they're going to punish someone in Yurp, or the US, or anywhere else for insulting their country? To me, that's a stretch.
For one thing, just imagine the logistics: it would require a vast surveillance network to even accomplish this. People (maybe not so many here on this forum but among the general public) have this Hollywood-tinted idea that this could be done in some automated fashion, using advanced voice recognition and AI. But at some point some poor human is going to have to sift through all the incoming reports, throw out false positives, massage the data. I don't think even China in its maximum-paranoia mode would be willing to spend what it would take to cast the net that widely.
I could be wrong about this, of course, but that's my belief at the moment.