Yeah I kind of wonder if a lot of the stuff about them breaking when left empty is that they won’t be suitable as a swimming pool anymore, rather than that they become a death trap. And if you don’t value the idea of a swimming pool, or it’s already so broken it would need expensive overhauls or replacement, then a walipini with a cracked foundation isn’t really a big deal.
But it comes up in every discussion I’ve found about empty pools, so I’d want to identify any precautions or mitigations to include before I start the sketch