@andrewgaul: Thanks for explaining the logic. If I understand correctly, this is specifically a problem in cases where we know we will get a non-2xx response code? In that case, could we create a separate test case that explicitly expects a 401? In such a test, I can indeed imagine that we would work around this problem in this way...

Would you agree with the assessment that this is annoying but not really a _jclouds_ bug because
* the Expect: 100-continue header is necessary/should be there
* the actual HTTP call that causes the problem would, in general (although not here in this test) not be made via jclouds

If either of those two assumptions is incorrect, should we be filing a bug to either not set the header or make the jclouds HTTP utils handle this case properly?