There are a lot of steps a university can take, even without a risk of getting sued:
* Cut 25% of your journal subscriptions to the worst offenders and keep cutting every year with some smaller percent.
* Publicly recommend to all scientific boards that the hiring process should judge applicants by the merit of their publications, not by their journal's ranking.
* Promote open-access submissions by your researchers: a small monetary bonus would probably suffice.
* Lobby your government to drop funding allocation based on journal rankings. Instead, promote some sort of combination of citation count [1] and expert consensus.
[1]: I realize currently the citation count is correlated with journal ranking (because the impact factor is computed by an average citation count) but it does not mean it is a bad measure. Plus of course, a comment on HN should not be the right place to design a really fair publication metric.