OK. That is good to know.

New items aren't auto-checked (as users may not want them selected).

Good suggestion. I checked, and sure enough, the newly created playlist was not selected. When I had setup WiFi syncing, I chose the default settings. These default settings included a check mark by playlists. I understood this to mean that all playlists would be synced. If only a partial list is to by synced, there is usually a square instead of a check mark. I think that is what caused the confusion, but it seems to be sorted out now. Thanks.

2) Is the new Playlist selected though?

I'm running MMW 1662 and MMA 168, and I'm syncing with an Acer A500. Previously I had been syncing via USB. Today I was finally able to sync via WiFi. Initially there were some problems that were caused by quirks that occurred during the previous USB syncing process. So, I cleared all the MMA memory on my tablet, deleted all the MM folders and all the music folders on my tablet, and then I re-installed MMA. I setup WiFi sync with the following settings:
Auto-Sync server content : Checked "Music" and "Playlists"
Auto-Sync device content: Checked the box

I initiated a sync, and all the music and playlists were synced from MMW as expected. However, now there are two problems.

Problem 1:
Every time I sync, MMA says,
"Playlists to update on the server:
Recently Added Content
1 playlist"
This occurs with every sync, even though there are no changes that have occured in either MMA or MMW.

Problem 2:
After the initial sync, I created a new playlist on MMW, but that playlist does not sync with MMA. I double-checked the Wifi Sync settings under "Auto-Sync server content" and "Playlists" are still checked.