prwhite said: "It’s unclear who will be the ultimate arbitrator for these concerns. The FAA is in charge of aircraft safety, but questions of privacy or trespassing could be left up to the states" and "Thorny legal questions come to mind"
There are 2 main sets of legal concerns that would affect an answer to your question because laws, rules, and regulations are not clearly defined for commercial drone usage for private package deliveries...
1.) What would be the correct legal venue to pursue a legal claim for legal injuries suffered from a delivery drone strike? Federal Laws and Regs take precedence over each State's Laws and Regulations regarding aviation. Regulating delivery drones for public safety could be regulated and/or restricted for any or all of the following government groups:
a.) Federal Courts (Judicial Branch of Government) make the final decisions on drone strike legal responsibility based upon legal facts presented in Federal Court
b.) Federal Aeronautics Administration - FAA (Executive Branch of Government) administers the application and policing of rules and regulations regarding Drones
c.) Specific Laws and Regulations passed by the US Congress (Legislative Branch of Government), but these legal oversight is often delegated to Congressional committees or Executive BHranch such as the FAA.
d.) State and Local government Laws and Regulations that may vary by each State or Local Government.
Currently, anyone operating a commercial or hobby/entertainment drone has to register and pass a written test from the Federal FAA. I believe that drones may have to glue an assigned FAA registration number clearly visible on the exterior of the drone body. Use of any drones around public or private airports is restricted due to safety concerns. Some States such as California regulate the use of drones in airspace over private property from 0 - 1000 feet altitude due to "Paparatzzi" often taking unauthorized pictures that violates the personal privacy of the property owner.
2.) Would the person flying and/or owning the drone be liable for civil and/or criminal penalties if their drone crashed during a commercial package delivery attempt? Once again, The Court Legal system would ultimately decide legal responsibility for a drone crash, but there could be a mix of State and Federal Laws and Regulations that could apply because this legal scenario is relatively new with no single government group solely responsible for investigating these concerns.
Civil legal damages based upon the evidence are presented in Civil Court and intended to compensate for a legal harm people experienced by a drone crash and restore those people back to their way of life before the drone crash occurred. Punative legal damages are awarded when Civil Courts decide there was wilfull intent or reckless disregard by the operator and/or owner of the drone that resulted in the drone strike. Criminal penalties are separate Criminal Court cases decided where there was an alleged violation of a declared Federal or State Law/Regulation that resulted in the drone crash causing a legal harm.