Preface: I've only been playing low level BGs as a twink Alliance Warrior.
I have no problem abusing consumables in battlegrounds. However, I don't go insane with them because, past a certain point, they're really not going to help THAT much. If I'm a twink on a team of f2pers in WSG, using one speed potion isn't going to help if the rest of the team can't kill the EFC. Aside from engineering items, like Portable Bronze Mortar or Discombobulator Ray, I don't use too much, otherwise. In the 10-19 bracket, I used Goblin Gliders to reach the mines at the start of Arathi Basin, because if I didn't, the other team would, and we would be at a severe disadvantage. Similarly, I was playing WSG in the 20-29 bracket today on a team of f2pers (I was the only 29 twink), where my team was surprisingly competent in killing EFCs, but not in protecting or healing me, so I used Free Action Potions to help carry the flag. In a bracket where my class is at a disadvantage, due to a lack of crowd control or means of dealing with crowd control, I have absolutely no problem using consumables within the rules, to level the playing field.
That said, I would never hack or outright cheat, of course. In one match of WSG, I was plunged into a losing 0-2 battle. The team was getting heavily corpse camped at the graveyard. One of the guys messaged me, saying that they had a Warrior using a cheat mod, but didn't elaborate on what or how it was doing. All I could see was that he had over 2500 health, when my 29 twink was just under 2000. I don't know if that was specifically what he was doing, or if the teammate was just making it up. Do you know about any new cheat mod going around in PvP?