It becomes inherently difficult to make datasets actually anonymous the more data points they have about a given individual - it doesn’t much matter whether names and such are listed data points if they can be inferred from the rest. This investigation by Svea Eckert and Andreas Dewes, for instance, managed to identify a named German member of parliament (Valerie Wilms) and other public functionaries within a data set on web browsing habits they received from data brokers.

Most countries do have data privacy legislation and relevant regulatory/enforcement agencies, but the data brokerage business is big and intensely international so the picture on audits is kind of unavoidably complicated.