In theory you could run an exit node with a locked down exit policy, e.g. limited to web traffic which is routed through an IWF compliant proxy, disallow HTTPS

In theory you could run an exit node with a locked down exit policy, e.g. limited to web traffic which is routed through an IWF compliant proxy, disallow HTTPS and/or payment processing sites, add an HTTP header for reporting abuse/requesting blocks, etc.