I could be wrong - Trish may know more - but I think the reason for bassinets not meeting safe sleeping guidelines is because they have solid sides. The recommendation is to have as much air flow around baby as possible, and so a bassinet restricts that a bit. A standard for bassinets would probably say they need mesh sides or cot-like sides.

Just another reason the new Amby Air is a good one I guess, it already has mesh all the way down to the mattress. I'm just disappointed I can't afford a new one and have the old kind!