PackGuard is a fairly small mod that helps modpack creators avoid false bug reports.
It monitors the mod list, and looks for modifications. If the pack has been modified by the user, the mod will tell the user to not report any errors. It will also leave warnings in crash reports and the log to help the pack author identify invalid error reports. The mod is easy to setup, and generates a simple configuration file called PackGuard.cfg.
Just go ahead and use it. Give credit and all that stuff.