It wasn’t anecdotal believe me.
When I was in training our drill sgt wouldn’t let us use the MRE heaters because he said the enemy could smell them. But in Iraq, the only thing you can smell is burning piss. Point is, in modern warfare, electronics give us much greater range than our senses, so although potentially real, the problem is mitigated. I can also assure you that combat readiness is much more greatly affected by fraternization issues than the scent of blood.