Completely agree. In a way I think it's almost the most difficult area to deal with, since apart from anything else you're not just dealing with some abstract object, you're dealing with peoples lives.
I remember putting together a DR plan for a company I used to work for years ago, and the difficulty of simply getting through to the Directors the concept of "what if you're not contactable" in terms of simple things like having the authority to pay for things to be repaired / replaced quickly was the main stumbling block of the whole thing.
There are a few simple things you can do though, for instance ensuring there is a chain of contact to allow you to contact all staff in the event that your systems (and therefore easy access to your normal contacts system) are not available. Something like ensuring all management have each others mobile numbers on their phones, all line managers have their own team members on the phones. If something goes badly wrong then a few phone calls can quickly spread the word. Also, if you're getting your techies in to work through the night to get things up and running again, have you pre-approved things like ordering in pizza or booking a hotel room? It's a tiny thing, but in the heat of the moment you don't want to be worrying about who's going to pay for it, will the company refund it etc, you need to be concentrating on getting the work done, and know that management will support that.