I hadn't heard that detail. An illegal seizure without a warrant should allow the victims to sue the agents in their individual capacity for a 14th Amendment "under color of law" violation. If it survives the FBI's inevitable challenge, the agency wouldn't be able to pay the legal bills of the agents.

Even if they don't expect to win, putting a dozen FBI agents in the position of having to pay for their own defense, potentially losing their savings and home in the process, should prompt the FBI to reconsider releasing the seized property.