Automatic opt-in Plans - Still a Good Idea?

The Pension Protection Act of 2006 formally allowed for the existence of 401(k) plans where employees could be automatically enrolled by their employers. The hope was to take advantage of most people's tendency to be, well, lazy. After all, human nature seems to be to leave well enough alone. For many years that meant paltry workplace retirement plan participation rates despite some fairly obvious and significant economic incentives (e.g., matching programs featuring guaranteed 100% return on contributions).

I was in favor of the automatic opt-in concept then. I still am today. However, I wish the timing of the initial legislation were a little better. I'm still waiting for the uproar from those people who lost money in their 401(k) plan when they never really planned on investing it in the first place. Keep in mind, the legislation also allowed for companies to invest the retirement money in funds other than the historically safe but typically under-performing stable value variety. As such, many of the folks who had their money diverted to the 401(k) plan also had it invested in the market so they experienced the stock market losses as the rest of us did.

Are you still in favor of the automatic opt-in or should we just let people make their own mistakes?