If you did not take off and land from park property, they dont have a leg to stand on. They can not regulate airspace above their parklands.
Ordinance 38, Section 409.3
"409.3 Operate self-propelled (motor driven) Unmanned Aircraft System (UAS aka “drone”) model aircraft, boats, automobiles, or other model craft of any kind or description, or fly any UAS closer than 500 feet above District parklands, as defined by Federal Regulations; (rev. 4/16)."
This is a definition of their "
District." They are not a federal authority. They can make up their own rules, but they cant control the airspace. Their tactic is to scare you off by giving you a citation, and make you go to court. Most people would just pay the fine, and not do it again. You were within your rights to fly there. The bad news is that a
District judge will probably side with the police, whether or not they are wrong, and then you will need to get a lawyer if you want to contest it.
SECTION 101. DISTRICT DEFINED. “District” means the East Bay Regional Park District, and includes all lands and waters owned, controlled, or managed by the East Bay Regional Park District, which shall hereinafter be referred to as “parklands.”
https://api.municode.com/CD/Ordinances/15400/769233?forceDownload=true
One last thing, and Im not sure why this got stuck in my craw. I called the East Bay Park Police and they said they are not a federal entity, just a district entity. They patrol some federal land but can not enforce violations.