Even if they don't explicitly invoke bash, it's possible that they call a program which calls a program which invokes a bash script somewhere. Debian switched

Even if they don't explicitly invoke bash, it's possible that they call a program which calls a program which invokes a bash script somewhere. Debian switched /bin/sh to link to dash a while back, but some maintainers decided to simply change the #!/bin/sh at the top of the shell scripts in their packages to #!/bin/bash rather than remove the bashisms. dhclient is the worst offender in the current kerfuffle, but I'm sure there are others.