 Like usn-stability, the concept of rwb-stability can be more discriminating if it is relativized to a particular set of strategies. Molander's 1992 investigation of Schelling's many-person version of the PD, for example, restricts attention to the family \(\{\bS_1,\ldots,\bS_n\}\) of TFT-like stratgies. A player adopting \(\bS_i\) cooperates on the first round and on every subsequent round after at least \(i\) others cooperate. By construing stability as resistance to invasions by other family members, Molander is able to show that there are conditions under which a particular mix of two of the \(\bS_i\)'s (one equivalent to \(\bDu\)) is uniquely stable. The significance of results like these, however, depends on the plausibility of such limitations on the set of permissible strategies.