I think this is exactly what is interesting about nostr. Hashes and signatures buy you a LOT. In theory, all you have to do is validate them, and you know you're dealing with good data. In practice though, there's an entire meta layer on top of the data itself defining the schema. Even if this schema is well-defined, every possible malformation has to be interpreted. In many cases malformed events can just be ignored, but there has to be some ability to tolerate a slightly different version of events. In a negative light, this leads to undefined or broken behavior, but in another sense it leads to emergent behavior — i.e. the ability to use existing structures in new ways.
Maybe someday all the clients will use LLMs to interpret events 😂