Let me specify that I'm not talking about doing a chemical attack on your own troops and saying that the enemy did it or doing a chemical attack on the enemy and saying that someone else did it. I'm talking about tricking the enemy into thinking that chemical weapons have been deployed at a tactical level.
As an example, mustard gas and chlorine gas are some shade of yellow and yellow-colored smoke exists for military applications and all of a sudden, we're lobbing yellow smoke shells at the enemy. We know they're just smoke, but the enemy isn't too sure. The assumption is that the possible deployment of chemical gas is enough of a threat that seeing a yellow cloud coming your way means getting at least a gas mask on and not "oh, we're getting marked for an air strike."
Threats of and/or actual retaliation aside, what are the consequences of using smoke to trick the enemy into thinking that they're under chemical attack? Tactically, it sounds feasible because you're making the enemy fight in reduced capabilities because they're either retreating, putting on protective gear, fighting in restrictive protective gear, or scared shitless. It's basically psychological warfare with practical effects.
Personally, I don't think it's a war crime because nobody's using any actual chemical agents—it's just things that look like chemical agents but are not. Placebos, even, with or without the physical and physiological effects.
Discuss.
