I think the icra/PICS method should be good if they'd adopt it. Plus, I believe it can be setup at server level to send the "adults only" tag(s) on each request.
If this was standardized, then esessentially all we SHOULD have to do is have our servers send the "warning", and it would be transparent to us.
Plus SE's could read it (if they felt like it) and only include it if the users preferences were set to "dont censor".
That could all make too much sense though, it's government after all
