Does the service provide any "proof" of performed screenings?

Yes. In addition to a response delivered as JSON you are able to request a PDF report that shows who performed the search, when the search was conducted and which data that was used to complete the search. The report shows what data that was collected and which lists that were screened against and the results of these screenings.

If there are no results against any lists the report will document which lists that was screened against at the given time. The report will be "stamped" by BankID and can be used to demonstrate performed screenings and their consequent results.