"If you are close enough to describe any insignias or symbols, you are laying there dying or you are a prisoner."
I understand that. But they reported being attacked by the Mexican army while on American soil - that's a big deal. If they didn't see any insignia or symbols how did they identify "the attackers?"
Probably because of the vehicles they were driving, one man giving orders to all the others men, the fact (presumed by me) that they were all carrying the same weapons, etc.
I can recognize a military unit from a mile away almost with my eyes closed.