Keeping active on the server will do you no good as it's a channel mode (+Z), not a server mode.
I suspect (not confirmed, and Rizon's explanation is not clear) that what they're doing is stopping your messages from posting to the channel (as well as everyone else's), so it would do you no good to have an anti-idle message every 10 minutes or so, either, because it would only make your messages show for everyone else, and not allow theirs to show for you.
I spend time in several CHAT channels, and have no issues at all with this (they are mode +Z by default when they're created).
