don't have a better way, but this would be a good thing (if you're not planning to already) to post as a failing test case to the module's RT, with either the patch you described or maybe just a reference to this thread (especially depending on the replies)..

A good basic double-check (obviously not complete, since you found this issue in the first place) would be to hack Class::Phrasebook w/your solution and make sure it still passes the test suite (and the previously failing foo/bar test)...