I still haven't heard why Half-Life gets away with it.

Maybe they get around the system by making it slightly faded/beat up looking.

Green crosses mean that there's a medicinal marijuana dispensary around here.

The whole idea that in game things should be restricted this way would make more sense if they hadn't been ignoring the issue for decades. Most games I can remember when I was a kid had first aid packs that had that symbol on it.

Now, if they sell physical items with the symbol on it, that might be worth worrying about. But, most first aid kits have the symbol on it already and I doubt most of them actually have formal permission to do it.
Right, technically this is a violation, but it's rather dishonest for anybody to think this is a big deal. A big deal would be going around in a warzone wearing the symbol while engaged in combat. That, would be a big deal, and that kind of thing is what this rule is supposed to prevent. That and people using the symbol as a way of getting around without being attacked.

Using it like this, just weakens the support there might be for the protection of the symbol.

That's also the avatar for Theme Hospital. :P

No wonder I always get hungry playing it.