A Facebook tool designed to inform users about the advertisers trying to target them through the platform withholds key information from consumers that get too curious, even locking them out when they use it too many times, according to a report in Bloomberg Businessweek.

From Bloomberg Businessweek:

Rather than providing unfiltered transparency, this Facebook function is instead feeding users frequently misleading—and sometimes untrue—reasons for why they’ve been targeted, Bloomberg Businessweek tests of the function suggest. The findings are corroborated by a new academic study of thousands of test ads that found Facebook’s explanations, “often omitting key details that would allow users to understand and potentially control the way they are targeted.”

The report’s anecdotal test of Facebook’s function is backed up by a similar, larger-scale study by researchers.

“Across all our experiments, we consistently found that Facebook’s explanations are incomplete and sometimes misleading,” they wrote (italics included) of their research, which was funded in part by the U.S. government’s National Science Foundation. Their data pointed to Facebook giving users the broadest targeting criteria (“you are in Italy”), rather than the most determinative (“you like far-right websites”), though it was impossible to know for sure how the complex function was built. “If this is in fact the case, this choice opens the door for malicious advertisers to obfuscate their true targeting by always including a very popular attribute,” such as the large group of those who access Facebook from mobile devices, they wrote.

Bloomberg Businessweek also reports that Facebook locked them out of the transparency function if they used it too frequently.

Facebook can also remove barriers to openness, like the one that got me blocked for being too curious. As I scrolled through Italian political ads, Facebook repeatedly froze me out of the “Why did I see this?” function if I clicked on more than 10 ads in a few minutes. Hural, the product manager, said the blocking is part of “standard privacy protection efforts.” It allowed me back after a cooling period of less than half an hour, making it a minor nuisance, though a symbolic one.

Read the full report at Bloomberg Businessweek.

Allum Bokhari is the senior technology correspondent at Breitbart News. You can follow him on Twitter, Gab.ai and add him on Facebook. Email tips and suggestions to allumbokhari@protonmail.com.