Bash before 1.13 also used the 8th bit internally for quoting.

I couldn't find a release date for Bash 1.13 but 1.14 was released on the 2nd of June 1994, according to this release notice - so that's a few months before Perl 5.000. If anyone is still running a version of Bash prior to 1.13 they'll have substantially bigger problems than this.