This reminds me of an interesting anecdote from Patrick Moore:
"When I left Greenpeace it was in the midst of them adopting a campaign to ban chlorine worldwide. Like I said, ‘you guys, this is one of the elements in the periodic table, you know; I mean, I’m not sure if it’s in our jurisdiction to be banning a whole element."
There is no government in the world that could possibly introduce legislation that says "ban mercury" without details, caveats and exemptions. That would be like saying "ban dihydrogen monoxide".
Let's look at the RoHS legislation, for example. RoHS says that lead, cadmium, hexavalent chromium, mercury, PBBs and PBDEs are restricted.
But RoHS has - and it needs to have - a list of exemptions as long as your arm. For example, suppose you have a solar cell based on cadmium telluride or a light-dependent resistor based on cadmium sulfide or a piezoelectric transducer based on lead zirconate titanate. These technologies have no realistic lead-free or cadmium-free replacements, so they're exempted from RoHS.
They don't just say "these elements are banned, period"... that would not be realistic at all.
Look at the Montreal protocol, for example - it certainly does not just say "CFCs are banned, period."
If we said "Mercury is banned in manmade technology, period", that would mean banning mercury-vapor discharge ultraviolet lamps used to erase EPROMs, for tanning, and for sterilisation in medical facilities and microbiology laboratories. It would ban essentially all fluorescent lightbulbs.
It would ban all high-pressure sodium lamps and the like that contain mercury.
It would ban all coal-fired power generation, since this is responsible for by far the largest share of man-made mercury emission into the environment.
And presumably it would ban tuna products, too.
It would ban the use of thiomersal as a bacteriostatic preservative in mascara, eyedrops, contact lens solution, antivenoms, immunoglobulins and other drugs, not just vaccines (most vaccines don't even contain thiomersal, anyway.)
It would ban the use of mercuric acetate and aluminium amalgam, etc, as catalysts and chemical reagents, both in industry and in the research laboratory.
It would ban the use of mercury standards for mercury analysis by analytical technologies such as atomic absorption spectroscopy. It would ban the use of mercury compounds for calibration of NMR spectrometers for Hg-199 NMR.
It would ban all use of HgCdTe and HgZnTe in infrared detectors for IR spectroscopy, IR astronomy, various types of sensors, FLIR imagers, night vision, military technologies and so forth.
Obviously it's nonsense.