[xmcp123]

This sounds a lot like “you’re getting analyzed by AI/ML, tied to a specific bucket of similar users, then your continued data expands the bucket, splitting off into different adhoc buckets of similar users”

If so, you can’t be tied to a specific purchase but you can be so tightly grouped it’s basically the same.

[shostack]

Look up differential privacy. Done right, it is impossible to do what you said.