Earlier quoted context omitted.
Nerve agents can kill you even with a gas mask. They absorb right through your skin.
That's still much easier to defend against than high explosives, and probably much harder to procure. If narco-terrorists can get blocks of C4 and cheap drones, why bother with the extra steps and international attention that a nerve agent would get you?
It may be sci fi at this point but it seems entirely possible to me. After all, mosquitoes exist and their behaviour is quite sophisticated. They’re able to locate mammals by detecting our breath, bite us to steal some blood, then fly away their eggs.