Firefighters are not 100% honest.
Check Google and you’ll find the ironic fact that numerous firefighters have been convicted of...wait for it...
Arson.
You’re welcome. (-:
Many worker's comp insurers regard a claimant's volunteer firefighter status as a flag that needs to be cleared in a claim. It's not unheard of for a volunteer firefighter to sustain an injury responding to a call, and then claim to have sustained an injury at his day job.