It's probably pretty easy, because in addition to what is being bought, Visa knows where the purchases occur. Most people have two clusters for their purchases:

It's probably pretty easy, because in addition to what is being bought, Visa knows where the purchases occur. Most people have two clusters for their purchases: work and home. A person who develops a third cluster may be having an affair. If you know what's being bought, you can figure it out with even higher probability.