So, let's say there's a battle that nobody sees but some people hear. One person kills the other, and immediately identifies their body as T. Now, someone could have shot either of them for firing and been justified in their actions, but after the inno has identified the body as T, they've clearly exempted themselves from that. My question is how long after the battle can someone still kill the inno and claim that it was done for firing at someone else? If it's one second, then sure, I can see someone's reflexes or lag being high enough that they didn't see the popoup saying he identified the body. Three seconds? Five? I've had people shoot me as much as six seconds after a fight, claiming it was because I "was firing at someone else," and the admin on at the time didn't slay them. Twice tonight it was about three seconds.
Simply ID'ing a T body doe's not mean you are exempt from anything, but with that said killing on suspicsion is also not allowed, so killing someone because you heard gunfire is RDM. Giving dumb people benefit of doubt, id say 5-8 seconds after. According to your scenario though "nobody see's but some people hear" It would be RDM right off the bat because you cannot act on what you hear, and Id'ing bodies does not prove you one way or another..
As far as if you and a traitor are in a firefight, staff usually give a period of 3-5 seconds after you ID the body to be killed; with hype of the game, they could already be focused on killing someone for a traitorous act, which they should, rather than the top right of their screen to see what the body is. Anything after that 3-5 seconds is RDM if they shoot you. Unless, however, you commit a traitorous act.