<SNIP>
The New Scientist has an article on how they can spot junk mail, just by checking if the purported sender is the same location as the source. So simple isn't it? In fact there will be a bit of software on all servers needed to make it happen but those that don't do it will be the focus of a lot of attention and policing I suspect. It will take time and effort though. It may take money - ours!
</SNIP>

This idea has already been rubbished in the computer press. Anybody who is home working may "spoof" their business address when mailing from their personal connection.