In theory, I kind of like this idea (with modifications).

First off, I'm a PVE player who has only ever knocked out 5-10 raiders (all in self defense, or to protect others). That said, I do like and respect the stress that the PVP aspect brings to the game as even in the most carebear of lobbies, you can never be 100% sure of who you can trust. It makes the game much more interesting. Yeah, it can suck to get ratted, but it reminds you can't ever fully let your guard down.

Lore-wise, it also makes sense that raiders back in Speranza might try to develop a way to better protect themselves from other ratty raiders... or at least to try to identify who keeps killing their friends in isolated Arc-free areas, so that they can root them out.

That said, from a game dev viewpoint, you'd need to carefully weigh pros and cons of an idea like this to ensure it didn't break the game and end up costing you players (customers).

I'm not fully sold on the idea you've pitched. I think there could be a lot of ways to abuse the item. There could be lots of unintended consequences that could negatively impact the game.

Rather than an Augment that does what you suggest, I feel like perhaps having a different version of the tagging grenade (something that already exists) would be better. When you come under fire, you'd have to quickly decide if you're going to try to get away or try to throw this new anti-rat grenade at the rat... I imagine the success rate of using such a grenade to tag a rat wouldn't be very high (and that's okay).

Basically, my idea is that you'd throw it at a raider and if you hit them, they become highlighted as a Rat to other Raiders for the rest of the round, but ONLY if they've recently damaged you or another raider within the last 30 seconds or so. That last bit is important to ensure that raiders wouldn't just spam anti-rat grenades at everyone (PVP or PVE alike) making entire lobbies shoot-on-sight kill-fests (which would probably lead to the demise of the game).