When a queue is deleted any bindings are also deleted. However, they are not removed from the persistent store if they have been added previously. If the same queue name is then used in future and the broker later restarted these bindings can be recovered and lead to unexpected behaviour. For example this can lead to problems with durable subscriptions when the same subscription name is used over time for differing subscriptions (eg without selectors initially, and then with selectors later).
0.6 and trunk is no longer affected, however the 0.5.x branch is.