While I do agree with the general concept of letting some factions go off the hook of necessity of dropping /1 /2 before engaging in a fight, I'm afraid BHG ID isn't one of them, due to the fact that it has unlimited ZOI.
But, this exclusion from the engagement rules should be applicable to the Nomads and Wild Pawns. Or, simply put, alien IDs. You have to agree that it's kind of silly when a Nomad has to drop two engagement lines before opening fire. Especially when it has to be right after the said Nomad drops out of its cloak.