Currently, there's a bug that basically prevents the software keyboard from being useable at all unless you slide the Motorola Droid's Hardware keyboard out while in the Seidio Car Dock. For giggles, a Verizon wireless rep let me test out the official Motorola Dock to see if the software keyboard works while the phone was in it's dock. Lo and behold, the software keyboard works just fine.
The issue is the location of the magnet. Many of you could test it with a magnet from a phone pouch/case. You can activate Car mode with the appropriate magnet, however if it is not directly in the exact place it needs to be on the phone, the software keyboard doesn't work. (I tested this myself on the store's pda pouches)
If you slide the Droid out of the dock just enough so that you aren't charging it, you'll find that you'll still have Car Dock mode activated, AND the software keyboard works again.
What this means, is that to get full use of the droid in landscape mode while in Seidio's Car Dock, you'd have to void the warranty, tear apart the plastic casing and drill out about 3 millimeters so the magnet slides down that 3 millimeters to appropriately add full functionality of the Car Dock Mode.
These have been my findings with my non-rooted Droid. Please test my findings out for yourselves.
For me, this would explain why though there are reported issues with the software keyboard not working while in car dock mode, the reported issues seem small and not as common. There would only be a small minority of Motorola Droid owners out there that would have known and/or purchased the Sedio Car Dock compared to actual Droid owners. Motorola's designers probably cannot replicate this issue as well seeing as how there would be no reason for them to buy a Seidio Car Dock to test for themselves. They would only use their own designed cases/docks.