Board Thread:General Discussion/@comment-22926615-20130924000856/@comment-98.24.238.102-20140121170756

Only in the sense that it hasn't been proven to have been successful. This Wikipedia list details the known escape attempts. All are considered failures according to official records, although one or two remain somewhat open-ended.

http://en.wikipedia.org/wiki/List_of_Alcatraz_escape_attempts