"Deletion-compliance relay crawlers" sending then deleting notes from random nsecs could do a reasonable job of flagging relays that didn't comply (whether they claim to or not). Couldn't detect "logical deletion" this way, though. So likelihood of a copy somewhere is high.

add to, but not delete. views may change and having a chain of custody of those ideas is critical to the built identity. or do those laser eyes not mean you are a bitcoin drooler? thus i must ask: what do you imagine the blockchain to be if not a series of valuable custodial opinions which evolve over time.