Ok, let's say I am not the jailor and I claim to be one. One of two things will happen:
- The real jailor simply jails and executes me on N2 or straight up counterclaims me during the day.
- There is no jailor and people realize soon that nobody is being jailed and the fake claim gets killed.
Either way the end result isn't good and there's no need to investigate a jailor claim. Also, some evil roles come up as Not Suspicious. Like Godfather, Arso, Jugg, Vamp, Plaguebearer, etc.