I'll first refer you to my previous post about Clean Room Operations at JPL [0].
All equipment leaving Earth is sterilized. The thoroughness of sterilization varies from project to project, instrument to instrument, and the agreed to HW & Planetary Protection Plans. It helps ensure that equipment is not giving false readings. Serious money is also laid out for HW & Planetary Protection (there's a whole division of probably 150 people at JPL) and sophisticated equipment used to test for contamination.
However, if there was deviation from the original Planetary Protection Plan [1], it was likely to execute some other test, timing/scheduling conflict, or some other "administrative" reason.
And with respect to finding water on Mars, why would you send your robot to a polar cap or even a "lake" with visible/detectable water? If you're attempting to prove that water and water flow processes exist & are active on Mars, it's probably better to test a fringe area, hence, the 3.3m requirement.
Should that read all equipment leaving Earth from the United States? Do other countries with developing space programs adhere to the same practices? Does the US have agreements with other countries to make sure we're all on the same page so to speak?
JPL (& many other NASA centers) collaborate quite regularly with the International Space Community. ESA [0] being the prime example (Cassini-Huygens[1], MER [2], etc.). This also includes commercial collaborators as well like SpaceX, LMA, Ball, etc. The community is relatively small and quite professional about their work. They usually don't take shortcuts.
But to answer your first question, Yes. All HW & Planetary Protection practices are not equally applied by all collaborators. However, ISO 14644-1 [3] is now a 15 year-old standard, at least, for Clean Room work environments. Such practices and the HW & Planetary Protection Plans are for Project Managers & Principal Investigators to manage & implement. "Faster, Cheaper, Better; pick any two" [4] we always said in the Spacecraft Assembly Facility at JPL.
Agreements are in place for all projects, and, it usually in the Principal Investigator's best interest to ensure his instrument/subsystem has the best HW & Planetary Protection Plan in place. It ensures their instrument/subsystem is operating nominally and has the longest usable life possible.
All equipment leaving Earth is sterilized. The thoroughness of sterilization varies from project to project, instrument to instrument, and the agreed to HW & Planetary Protection Plans. It helps ensure that equipment is not giving false readings. Serious money is also laid out for HW & Planetary Protection (there's a whole division of probably 150 people at JPL) and sophisticated equipment used to test for contamination.
However, if there was deviation from the original Planetary Protection Plan [1], it was likely to execute some other test, timing/scheduling conflict, or some other "administrative" reason.
And with respect to finding water on Mars, why would you send your robot to a polar cap or even a "lake" with visible/detectable water? If you're attempting to prove that water and water flow processes exist & are active on Mars, it's probably better to test a fringe area, hence, the 3.3m requirement.
[0] https://news.ycombinator.com/item?id=6809134
[1] http://www.space.com/13783-nasa-msl-curiosity-mars-rover-pla...