Yes. This is the answer. There is no solution that relies only on technology that will fix human problems at scale. You can make it harder, but once one person figures it out, everyone has access to it. You need to break it into pieces and let people deal with it on the community level, where communities are small enough that people can deal with individuals.
The main issue is that 'at scale' you have the fact that a certain percentage of people are sociopaths, a certain percentage of people are really smart, and a certain percentage of people have the time and motivation to do something, and when they all cross you end up with a person who breaks your system.