Martian Invasion in 2012?

Well, more Martian Importation:

A Mars mission to be launched in October on a Russian robot spacecraft will include specimens of thale cress; tiny water creature tardigrade - or water bear - which can also survive extraordinary extremes of temperature and pressure; samples of brewer's yeast; and permafrost from the Siberian Arctic. Together with several other microscopic organisms, these representatives of Earth life will be carried in a package that will be flown to Mars and are scheduled to be returned to Earth in 2012.

Could it be that, due to our own stupidity, we import something alien and dangerous in 2012? I can't help but think some expert will declare a sample to be inert, and that will be mankind's famous last words....