The literature on the impact of queue length disclosure on consumer welfare and service provider’s revenue dates back to Naor (Econometrica, 37, 15–24, 1969). In Naor’s model, homogeneous customers observe the real-time queue length upon their arrival to the system and make decisions to either join the queue or balk. In other words, the service provider discloses full queue length information, and such setting has since been referred to as an observable queue in the literature. Edelson et al. (Econometrica, 43, 81–92, 1975) study the unobservable version of Naor’s model where customers do not have any queue length information upon arriving at the service system. They decide to join the queue or balk based on anticipations of other customers’ strategies.