I just wanted to note that Freewinds, the Scientology cruise ship, appears to have many of the properties that we’d want for a seastead, in as far as it’s more or less operating as a law unto itself, powered by what we might loosely call “religious tourism” (although that probably underestimates the degree to which its funding is drawn from the various other fundraising activities of the organization.)
Although it’s not a particularly appealing example, it does show that the basic model works and, with the correct support infrastructure, it’s largely immune to legal insult. I think it’s not improbable that the global libertarian community could run interference for seasteads at least as effectively as the Scientologists run interference for Freewinds in terms of political protection and support from the land-based nation states.
It’s an existence proof for quasi-autonomous sea-based activity in the modern age. They’ve been at this pushing 20 years, and that’s a good run, and it shows little sign of stopping.
It’s a good example of the downsides of being able to create pocket jurisdictions too – Scientology, FLDS (the texan sect) and so on might all make use of the seasteading tech as it matures.