It would make me feel better also, thinking that a planetary probe that finds microbes may actually be finding alien microbes.
Except for three small details...
1. It is *much* less expensive to send a probe into space that has not been thoroughly decontaminated, entirely constructed in clean rooms, etc. than it is to send a probe into space that is entirely, absolutely clean....so there is financial incentive to not observe the strictest of protocols.
2. Not all space probes are being launched by NASA. Different agencies have different standards. Then too, in an era of reduced budgets, there is always the tricky question of "how clean is sufficiently clean"? You can always get even more anal retentive, but at some point along the curve you encounter diminishing returns and increasing costs. It is possible that not all agencies would agree in all respects.
3. The person who is currently the Planetary Protection Officer for NASA is my cousin. She provides a sense to me of how very challenging this issue is.
Still, there are a number of extremely well-qualified folks in numerous organizations working on the issue - it isn't as if its going un-addressed.
FWIW. YMMV...
