Sad story... say you're a BFL customer and you opt for hosting to get your unit hashing ASAP - this seems like a straightforward option. You pay for your 60GH miner, hosting and you've got a June or July 2012 order, so you feel like you might actually receive the product. Then the power usage for the products change drastically and BFL doesn't have enough PSUs. Of course they give customers the option of shipping w/o the PSU and so customers can supply their own hacked PSU, but those that paid for hosting - they are now SOL and waiting behind everyone else. It'd be funny, if it weren't sad.
Luckily there's no way KnC runs into this problem since their products uses a standard ATX PSU, available everywhere.
The BFL Single is designed to run off a standard ATX PSU, what do you think the people that ordered with out the PSU are using?
From what I can tell, the whole BFL range can run of standards ATX PSUs.
KNCminer don't even give you the option of ordering with a PSU from what I can tell. Which suggests that you will have extreme difficulty getting insurance, as it is probably not electrically certified for your country. We will have to wait and see if that's the case, every country is different.