I see what you're saying. That makes sense that the clients that aren't deployed into the right group fall in the default group so that I can put them in the correct group using the management console. Which did work. I suppose that is the bug fix for release MR4 MP2?
Although I did test checking "block clients" in the default group and it appeared to work on a small scale. It might not work on a large one. I did have one client who did not appear in any group but when I used the "find unmanged computers" tool in the management console, the package deployed like a charm and the client was put in the correct group.
@plockel
I guess having clients appear in the "default group" is the solution so that as an admin they're easier to track and that way you can put them in the group they're supposed to be in.
I'll let you know how my mass deployment goes.