in reply to LWP::UserAgent : setting max_redirect to 0 yields 'Client-Warning: Redirect loop detected

That actually looks like a bug to me. The test should be "is greater than," not "is greater than or equal." I would open a problem-report to that effect. I think that what you have said should be understood to mean that redirects ought not be followed. But, really, there ought to be a follow_redirects (true/false) option to settle the matter. Meanwhile, I wonder what would happen if you set requests_redirectable to an empty array?