The function ViewDataTable::disableGenericFilters will set $this->variablesDefault[ "disable_generic_filters" ] to true, but this data is never used again. So the function has no real effect. This should be fixed w/o causing any regressions. I think currently only the Live plugin calls this function.
I think it's useful:
$requestString .= '&disable_generic_filters='.Piwik_Common::getRequestVar('disable_generic_filters', 1, 'int');
and is used in ResponseBuilder
if(0 == Piwik_Common::getRequestVar('disable_generic_filters', '0', 'string', $this->request))