As mentioned, it has sometimes been tried to pretend to be a seer in a lite, and it generally goes poorly. Wagon mentioned during the game his dubious attempt to pretend to be one of two seers with a 50% chance of having a successful scan each. Which maybe, very tenuous maybe, could have worked in a lite with an experimental set-up (and a couple times afterward where there were in fact two 50% seers), but in that game the rules were completely vanilla and no indication otherwise, so Wagonlitz got outed for it. The principle way in which false seer claims have been made has been in private to a singular "canned" villager, typically with the intention of then feeding them a name to out and then hunting them, denying the village a day of voting and potentially making the actual JL more public. This has very rarely worked out well, and one game I almost got in hot water for trying it since my pack hunted the seer night 1 and I'd false claimed seer to a villager day 1. He should've outed me day 2, but he mixed up when deadline was and so didn't.
What separates other instances where wolves have pretended to be seers from this one lies partially in that they did so in private and so did not come across as suicidally stupid to even the villagers believing them, but also they didn't out their packmates. It's such an insanely stupid and imbecilic idea to out your own packmates. Every dead wolf makes it harder for the wolves to win as it pushes back parity. What credibility you may buy is always going to be in jeopardy from the actual seer, and the longer the game goes on, the more likely your house of cards comes down. You have a situation where you are entirely sacrificing one member of your side for the very slim possibility another member of your side will avoid hanging for it. It's very unlikely to work, far more likely to backfire, and it's all so unnecessary compared to just playing the game normally.
And that's not even getting into the possibility that the person you're outing actually deciding they won't go quietly and spilling the beans on it. As happened here. Even if there was no initial belief in my claim of being betrayed, the possibility of Jam being a fraud had been explicitly put out there and likely factored into Jam rapidly accumulating votes day 2 after the seer was hunted. Aside from that, I had been planning to put the hunt on Jam himself for night 1, and the only reason I didn't was because it was instead put on a likely seer candidate, which I figured would help Arkasas and MAW (who were faultless in the whole affair and shouldn't be punished), as well as expose Jam for a fraud anyways. Had I known that he would go on to out MAW anyways, I'd have put the hunt on Jam regardless and done the pack a favor.