Just the other day I discussed with @jerry how I could trust him as instance admin. Short version: I cannot, but I can switch instances if he does something creepy.
Today this theoretical scenario is already reality for a friend. Her instance admin posted a creepy sexualized reply under her toot and, when called out on it, didn’t see anything wrong with that. This incident has shown two major flaws concerning Mastodon and abusive admins, one being of technical and the other of social nature.
In principle, jumping instances is easy. It doesn’t however allow you to move your existing toots. There is an ongoing discussion on that. One side is pointing out the abuse potential such feature would have, allowing to create fake backdated toots. The other side points out that Fediverse doesn’t make this kind of guarantees anyway, and an instance admin can always create backdated toots. https://github.com/mastodon/mastodon/issues/981
Jumping instances is only an option if there is an instance you can move to. With Fediverse being so male-dominated, it might be hard for women to find trustworthy instances. There is no code of conduct that instance admins have to subscribe to, neither a way of checking their track record. For women this means a tedious and emotionally demanding trial & error procedure in order to find a safe space.