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.
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?