Hive account@anyx -Wow - you do make an interesting point about Steemit having not completely solved the double payment issue. I guess the creators depended on the moral values being upheld by content posters. However, you are right, the blockchain, by itself does not prevent double spending that can be caused by re-posting by authors or plagiarism by some authors of old Steemit posts etc. In fact, when the Steemit interface had some issues couple of months ago, many Steemians ended up double posting content (they hit submit twice because the interface showed transaction error first time) and the exact same post got published and paid twice!
Thank you for the interesting treatise on double spending issue. Upvoted

Regards,

Hive account@vm2904