How can conversions continue to be leveraged to reliably detect and confirm IVT?

[acomets]

The most robust and reliable signal we use today as a "ground truth" for qualifying traffic is sales conversions. A user generating credit card sales/transactions can reliably be considered valid human traffic.

Today, we can transfer the knowledge that a user is legitimate across partners.

This requires to have a stable cross-domain identity which is what this proposal aims to prevent in the first place.

Therefore, how does this proposal intend to address this use case and to detect invalid traffic at the application level?