The Bermuda Post Office requires proof of physical address for billing and legal purposes. 

Individuals must have a physical address where they can be contacted and known to reside.  Companies shall always have a registered office in Bermuda which shall not be a post office box to which all communications and notices may be addresses.  (Companies Act 1981, Section 62, subsection 1). The referred law can be downloaded here. http://www.bermudalaws.bm/laws/Consolidated%20Laws/Companies%20Act%201981.pdf