In a strong letter to Lina Khan, the chair of the Federal Trade Commission (FTC), Rep. Anna Eshoo of California on Tuesday criticized the "significant Fourth Amendment search and seizure concerns" raised by Fog and urged the FTC to investigate fully. As public records obtained by EFF show, police often use Fog's mass surveillance tools without a warrant, in violation of our Fourth Amendment rights.

Eshoo wrote:

"The use of Fog is also seemingly incompatible with protections against unlawful search and seizure guaranteed by the Fourth Amendment. Consumers do not realize that they are potentially nullifying their Fourth Amendment rights when they download and use free apps on their phones. It would be hard to imagine consumers consenting to this if actually given the option, yet this is functionally what occurs."

Eshoo also pointed out the new threat that Fog's surveillance tool poses to people seeking reproductive healthcare.