Additional note (August, 2012):

The direction established by CWG for resolving this issue was to consider functions called from default arguments and non-static data member initializers in determining the exception-specification. This leads to a problem with ordering: because non-static data member initializers can refer to members declared later, their effect cannot be known until the end of the class. However, a non-static data member initializer could possibly refer to an implicitly-declared constructor, either its own or that of an enclosing class.