The event code to use to access the default event function is ET_DEFAULT. This event code is never posted by Vermont Views, and should never be posted from your code. It is a "fake" event code that is searched for if the desired event code is not found in the event table.
Keep in mind that the Vermont Views processing functions are designed to search more than one event table to find event codes. If you install a default event function in one of the Vermont Views function tables, the system will never search beyond that table. For example, if you install a default event function in the form event table FMETP, the form editor will search the system event table SYSETP first, then the form event table FMETP. Because the form event table now has a default function in it, the form editor will never search any of the item-specific event tables, such as FLDETP or SRETP.