When he’s talking about data tracking in the context of the current protest movement, Andy Ihnatko doesn’t care if you call him crazy.

“It’s OK if listeners think I’m paranoid,” the tech writer said Wednesday on Boston Public Radio. “As long as they’re aware that it’s really possible to glean a lot of information about who you are, who you’re with, what you like, what you dislike, and where you go, and what you might do in the future — simply by the fact that you’re carrying this radio beacon into a large group of people.”

The latest cause for concern, he explained, comes in the form of research from data broker Mobilewalla analyzing smartphone data from 17,000 Black Lives Matter protest attendees, mined without their knowledge or consent.

Last month, the company produced what Ihnatko described as “a very, very fine-grained report," released publicly, that analyzed information about protesters in Minneapolis, New York, Los Angeles, and Atlanta across three days in late May.

Read More: Andy Ihnatko On Protest-Proofing Your Phone

Mobilewalla claims to have data on “over 1.6 billion devices across 35 countries,” and been using this technology for several years. In a 2017 interview, CEO Anindya Datta explained how the company was contracted by “one of the major parties" to surveil evangelical voters in 2016.

Ihnatko said he’s particularly worried about how countries hostile to protesters might use the technology.

“Imagine a government that really doesn’t like people protesting on ‘this' topic. What if you wanted to find out … not specifically the names, but here are the demographics of the people who are at these protests, and now let’s figure out ways that we can keep these communities silent, and keep these communities afraid,” he said. "It’s a super, super scary thing to consider.”