Personally, I love the idea but, with disappointment, I can't pragmatically recommend it for all but the most minor of situations.
There are so many workplace rules and laws that violate common sense that you have to adhere to (e.g. many "harassment" laws) that spelling them out is almost the only way to avoid frequent problems (e.g. My wife was formally reprimanded for not inviting certain colleagues to an after work - and not work related - function. This is called "bullying" nowadays and we spent months dealing with the disciplinary case/suspension/etc. They now have a policy where you have to officially disclose who you are friends with or not and why. My wife no longer works.)
Update: I read too quickly. It seems they've realized the above and are distributing a book of policies too. A shame.