I decided to take a look at what other channels do today. I looked for channels similar and therefore directly comparable to Off the Charts: reputable, popular, mostly music-oriented channels that cast on a regular basis on Vaughnlive and are hosted by a live on-camera person at least some of the time. I found 27 such channels, including Off the Charts. A few of these channels are more beer-focused than music focused, and some don't cast on a set schedule, but I surveyed them anyway. I included "big name" channels like The Dog Pound and also the channels of friends and acquaintances of Off the Charts. All of these channels enforce an anti-troll policy. I looked at both whether or not they enable Guest Chat and also whether or not they use the Announcement feature.
I might have missed a few I should have included, and I might have included one or two that don't belong, but here is what I found:
The most prevalent combination among the surveyed group is having Enter/Exit announcements ENABLED with Guest Chat DISABLED. The 15 channels set this way are: 3rd Eye Vision, 82Mako20, Chillin' in Miami, Country Gold, The Dog Pound, Hank & Jim, Hatched54, Maineyak, Memorex88, PamJam, Phoenix True Oldies, Radio Memories, Reggieroller, Toenail, and Totally 70s.
Seven channels have Enter/Exit announcements DISABLED and Guest Chat also DISABLED: CraigTube, Fiddleheadj, IBM Network, Jake & Dar, Johnny Angel, RyChannel, and TartanTV.
Going the other way, just one channel has Enter/Exit announcements ENABLED with Guest Chat also ENABLED (that channel being Jay Muff), while four channels have Enter/Exit announcements DISABLED with Guest Chat ENABLED as of today: DJ Ledou, Hostile570, Off the Charts, and Steve James Barr.
Looking at Guest Chat alone, among the survey group 22 channels DISABLE Guest Chat while 5 channels ENABLE it. Note that the default condition of Vaughnlive chat is to have Guest Chat OFF. Whenever the chat server resets, all affected channels get put back to having Guest Chat disabled until the caster resets it again, so that might depress the "enable" numbers slightly on any given day.
Looking at Announcements alone, 16 channels ENABLE Announcements while 11 channels DISABLE them.
As a practical matter, the more popular the channel, the less appropriate either feature is, especially Announcements. The chat simply gets too cluttered and moves too quickly. As the prime example, I believe Craig is wise not to enable either feature in his most-popular cast.
Update October 18, 2015: Add one more channel to the Announcements-Enabled and Guest Chat-Disabled category: PC Music Radio. I should have included them originally. So that's 16 channels in that category, 23 surveyed channels in all that disable Guest Chat (excluding OtC which has now moved into that category - see blog entry above), and 17 channels in all that enable Announcements.
Update October 22, 2015: I found yet another channel in the Announcements-Enabled, Guest Chat disabled category: RadioRockCafe.