Under America's legal system, anyone can be sued for anything (whether liability attaches eventually--with or without a remedy--is a different kettle of fish). This, of course, includes sponsors of retirement plans such as 401(k)s. In just the last month, no less than a dozen institutions of higher learning that sponsor 403(b) plans governed by the Employee Retirement Income Security Act of 1974 (ERISA) (as well as those sponsoring 401(k) plans) have been on the wrong end of such lawsuits. These institutions include USC, Northwestern, Cornell, NYU, MIT, Emory, Yale, Penn, Vanderbilt, Johns Hopkins, Duke, and Columbia. At present, the plaintiffs' bar seems to be running wild, so it's possible that this list will be incomplete by the time this column gets published.
It's no accident that all these schools are private because governmental (i.e., non-private) 403(b) plans such as those made available by, say, K-12 public school districts or public institutions of higher learning don't fall under the aegis of ERISA.