Our platform does not pull impressions from activation platforms of your subscribers and we ask that our customers report the usage of this data on a monthly basis. This is particular to data feeds where subscription is at a CPM basis for all data providers in Marketplace. This is a trust-base agreement and does have a legal exposure to buyers if their reporting is not true.
The subscribers are not required to report usage for flat fee subscriptions.
Additionally, Adobe doesn't get involved in the billing process for private data-feeds. It is an arrangement between the data-provider and buyer.