The use of Android by enTourage merely saves them licensing fees ($$$). Since enTourage doesn't demonstrate a culture of openess, I doubt "open source" was the attraction.

Of course, saving licensing fees is what attracts every company to using Android on their phones/tablets when they consider what it costs to buy into the Microsoft camp. These other companies are saved the pain of an SDK, though, by having standard implementations of Android for their devices for which the standard Android SDK suffices for app development.