For info, Dan Buster, I am already on a base. Having seen the way the company moved over Amsterdam I am interested in discussions now taking place behind closed doors. When the company weighed the benefits of the Amsterdam base against the disadvantage of Housing Allowance, the base lost.
Willy nilly commuting, as Bonajet calls it, is already a fact in many jurisdictions, including the US, Canada and Europe. In order to distinguish between a commute and a base, a base is where your pattern starts. A roster pattern that started in HK would involve a commute. To re-iterate, the system is already operational.
As for tax; this does not currently affect the company, but since laws get changed it could be an issue for them in one, two or ten years time. Why deal with several jurisdictions when you only need deal with one.