In other situations, the initial data entry depends on a trusted authority rather than a trusted other party. For example, real estate ownership deeds depend on qualified legals who write them correctly: you need to trust them to do their job, without mistakes, collusions, etc. at which point there's little practical difference between buyers and sellers trusting them to keep a public, official record with paper and electronic documents in their archives and trusting them to enter your transfer into a public blockchain system.