I think there should be some kind of universal warning system which broadcasts emergency warnings such as the recent blockchain fork.
How it could work:1) Have a domain setup with simple JSON service with a few simple fields such as, alert status, alert message, more info link
2) A small select/vetted number of developers and community members would have access to update the status/alert message
3) Bitcoin client software could be coded to the check the warning system and show alerts.
Something like this:
For example I use Electrum, I received some bitcoins right around the time of the fork, in Electrum it was showing 6+ confirms, so I transferred out some money to the sender. When I later heard about the fork and potential double spends on transactions with less than 11+ confirms I just about shit myself. Luckily there was no double spend, but we can't really expect all users, merchants etc...to be constantly monitoring the forums and IRC to know whether they should trust the confirmed transactions in their wallets.
I think the main argument against this might be "What if the alert system got hacked or abused"....well at the end of the day what's the worst that could happen? Users see a "See sexy p0rn click here" type of message for a few hours? But if you compare this risk, to the risk of users being totally unaware of major network issue; I'd prefer to have the warning system.
If I get some feed back that people think this could be a good idea, and some devs would consider integrating it I'd be happy to setup and maintain the warning service.