Does the open door policy work?

I recently got into a friendly debate with a fellow business owner, about the open door policy.

"I have an open door policy, but all I hear are complaints. But I don't want to stop always having my door open."

The friend of mine is certainly not a rookie leader. He runs a 50 man company that is growing every year. And his staff like and respect him. So what gives?

The open door policy is certainly very popular in many places.

It's not surprising that it's popular. It brings with it some strong arguments for it:

1. People feel comfortable, knowing that they can raise issues any time, and be welcomed for it.
2. It gives leaders a much better sensing on what people are thinking or concerned about.
3. It removes the need to set up tense and sometimes awkward meetings; just walk in!

But how does it bear out in practice? The issue is that it can, sometimes, backfire:

1. People go to the leaders to rant or complain.
2. Unscheduled interruptions distracts the leaders.
3. When someone walks in, the leader may be engrossed in something else, and therefore cannot give 100% attention to the matter. Unfortunately, open doors do not equal open minds.
4. People learn to shun decisions, because decisions carry responsibility. Instead, they depend on the seniors or leaders to make all the decisions.

So the question is, is there a way to have all the benefits of having an open door policy, while minimizing the disadvantages?

To me, I feel some small tweaks will go a long way. Oh, and some ground rules.

1. Instead of simply "walk in when you want", we can instead do "let's always feel free to set up a discussion". With mutual respect for each other's time, then things are already off to a good start.
2. If the discussion is about a problem, then the person triggering the discussion should also be ready with at least a solution or two, about how the issue can be resolved. In other words, be ready to share "what have you tried?", and "what do you think might work?". That would naturally allow the discussion to be effective, rather than just be a rant.
3. When a leader has committed to a discussion, we should focus 100% attention for that time, to the matter at hand. Leaders are there to serve our people, to allow them to be as effective as they can possibly be.

What do you think about the open door policy, and have you had success with it?