The protected emblems

misuse is a war crime

Unicode: U+271A heavy greek cross · U+262A star and crescent · the red crystal is not encoded
The job: Make a person, a vehicle or a building legally untouchable in an armed conflict — and be recognised as doing so by someone who wants to shoot at it.
Standards: The Geneva Conventions and their Additional Protocols. This is the only symbol set in this institute whose misuse is a war crime: using the emblem perfidiously — to shield combatants or mask an attack — is a grave breach of international humanitarian law. Every other mark here can be misused badly. This one can be misused criminally.
Failure modes: The founding claim did not hold. The red cross is the Swiss flag with its colours reversed, honouring the state that hosted the 1864 convention, and was declared to carry no religious meaning — a declaration nobody outside the room accepted. The red crescent followed after Ottoman objection in the 1870s, and the red crystal was created in 2005 under Additional Protocol III specifically to provide a form with no religious reading at all. Three emblems exist because the neutrality of the first was asserted rather than achieved. The slower failure is commercial: first-aid kits, pharmacy signage and game health packs use the mark constantly, and each use makes it a little more ordinary — which is a direct attack on the thing that protects people.
Cultural flips: A mark designed to be neutral was read as Christian, immediately and permanently. The entire three-emblem history is the flip, and it is the strongest evidence on this site that a designer cannot declare what a symbol means.

Sources · 4

documented The Geneva Conventions and Additional Protocols, for the emblems and the prohibition on perfidious use.
documented Additional Protocol III, 2005, establishing the red crystal as a third protective emblem.
documented The red cross as the Swiss flag with reversed colours, adopted at the 1864 convention.
traditional The judgement that commercial dilution measurably weakens protection. Argued consistently by the movement itself; the causal claim is not something the Institute can evidence.