Privacy Act Stipulates Users Must be Able to 'Opt Out' 

Not Possible

SOVEREIGN SILOS EXPLAINED / NEXT

Blockchain solutions weld every aspect of users' interaction into an indelible 'shared ledger. By design, this can't be altered to remove a user's data. Doesn't work. Whoops!

The only way around this non-sequitur is to not put users' personal details into blockchain. Goes into a seperate *database. Enterprise vendors actually do this. Which is hilarious.