Tough call.He better have a pocket full of money and a cadre of lawyers if he gets nailed-- the fines they are considering will buy about 2 dozen P3's
Fines are levied as penalties for violations of administrative or criminal regulations. If you modify DJI firmware to disable a private database that prohibits you from flying over zones that are privately established but you self impose compliance with legally established "no fly zones" you are more than likely safe from the FAA and any other governmental action.
Not so clear is the issue of whether DJI would ask the feds to go after you for criminal "hacking" because arguably they could.
Also, not so clear is the issue if DJI would go after you in federal civil venues for violations of Intellectual Property protections.
However all that said, and by way of analogy, the FCC has not reacted in any way to the "more channel hack" which arguably extends the approved DJI frequencies into zones that are not approved for the Phantom 3 or Inspire and are very close to frequencies reserved for private radio operators. You will also note that DJI has not, as of yet, either asked the FCC to take action on its behalf, or brought private civil actions against any person for unauthorized modification of its proprietary firmware.
Just some food for thought