Allow both greenfields ---.kid and redlight areas ---.xxx
Provide a public service to identify sites that should be in redlight areas and are not.
Encourage producers of voluntary filters to use that list.
No single solution will be adequate, but a combination of technologies can do much to protect children from undesirable influences.
The producer-transmission-consumer system must be understood to make reasonable predictions of the effects of changes, inducements and constraints.
There is a cost to breaking the chain, and there must be willingness by parents and other participants to bear that cost, both financially and socially.