The sitewide moderator guidelines suggest that it's a good idea to allow community members to appeal their bans, and use that as an opportunity for learning and rehabilitation. Plus, it's often unreasonable to be permanently banned for your first infraction because you were new to Reddit, or made an honest mistake.

That's all well and good. But let's say your community has implemented a system of progressively more and more severe consequences (warning, short ban, longer ban...) for repeated rules infractions that already allows ample opportunity for someone to change their behavior before getting permanently banned.

Do you think it's reasonable in this case to state in the rules that bans of any length cannot be appealed? And perhaps even more importantly, could the community get in trouble for having this as a public policy?

The idea is to reduce moderator workload and emotional labor, make processes clearer and less arbitrary, increase perceived fairness and consistency and prevent the expectation that you can always try to talk yourself out of receiving a ban.