I looked into building a HERF generator and microwave cannon and found both to be simply too expensive and underpowered and short of range to be anything other than cool looking toys to trot out for physics lecture.

For drones at this present time, Saiga 12s with duck or goose loads seem like the best bang for the buck. Maybe try that coupled with a paintball sentry thats robust enough to handle the mass and recoil.

For preventing or reducing sabotage against the grid, a stable functioning high-trust society seems like a pretty affordable option.