I completely share the concern, that there needs to be a reciprocal agreement - improvements made to OSM data need to make their way BACK into OSM! If waze can't allow for it, 'that's a deal-breaker, ladies.'
Here's the part that concerns me though - the compelling piece about waze (and google navigation I can imagine), is that their apps will make it incredibly easy for anyone to add and improve map content: Just turn on your GPS-enabled device and drive. Waze/google nav users don't even see it as contributing to a project -- they're just using a valuable, free service (that just happens to create and improve street data).
Are there ways that OSM could partner with organizations to help provide this level of input - easy, and ubiquitous to the map database?