Hmmm... finally came around to trying Mobile Edition activated Network Wide on WP 3.0 RC2 in MS mode. The first thing I notice that the plugin does not populate its User Agents fields on any of the other existing sites except on the one the actual activation took place.
This resulted on my setup in the plugin only working on the main site. Other sites will not present the mobile theme to mobile browsers unless each site owner is cleaver enough to notice the Settings > Mobile page and hit the Reset links...
Same thing happens on newly created sites. the fields are empty.
Now I realize this can be seen as an advantage. A site owner has the option to disable the mobile theme by clearing those fields even when unable to switch the plugin off. But the downside is that site owners that have no clue how to go about and activate the mobile feature are lost.
Maybe just some little more explanation on the Settings > Mobile page to make it clear what the result is of the empty fields and how to activate the mobile feature (by Resetting it to Default) would be already great. But what I am really looking for is a way of making the plugin auto-populate these fields.
Is this plugin still being actively developed? If so, can I make some contributions to the code to make it just that little bit (even) more user friendly?