launchtl can be used to disable and re-enable crash reporting.
To disable crash reporting:
launchctl unload -w /System/Library/LaunchAgents/com.apple.ReportCrash.plist
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.ReportCrash.Root.plist
To re-enable crash reporting:
launchctl load -w /System/Library/LaunchAgents/com.apple.ReportCrash.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.ReportCrash.Root.plist
Disable mDNSResponder
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
Disable Apple Push Notification Service (apsd) on OS X 10.8
launchctl unload -w /System/Library/LaunchDaemons/com.apple.apsd.plist