Jester's are a fun role to play and claiming them as evil at a good spot in the game could be crucial to win a game. My suggestion is to make Jester slightly more of a Neutral Evil role by having any Town role that kills this role at night will commit suicide out of guilt, this includes Jailor and Vigilante (I believe they're the only town roles that can actually kill a non-visiting role anyway).
Why would this benefit them? This not only benefits them but also evil roles that claim Jester since the whole concept of "Jailor, jail and exe this because of possible jester" would be a little more risky and could be used as a one night buffer for evils or a way to weaken Jailor/TK possibly. Of course being lynched is still their goal so being killed at night this way would still incur a loss.
Thoughts and opinions?