I am not sure that a self-destruction device would be a good idea. The Chinese have obviously put a great deal of time and $$money$$ into the mission. Having the probe self-destruct at the first sign of trouble would be kind of self-defeating. Although we are not certain that there are no more C-probes lurking about, we have not seen any direct evidence of any others. This leads me to believe that the Chinese (socialists or not) have "put all their eggs in one basket". I don't see them blowing the basket up themselves. (At least not until ALL other means have been exhausted.)
Taz