When a job seeker sets up a job alert, the default selection for “How often do you want to receive suitable jobs via email?” is set to “None”. This is not ideal, because the job seeker may not notice, and thus never get email updates. So you can change the default option (and order of options) by going to: views/jajobalerts/view.html.php starting line 224. It should look something like this:
$htmlOptions[] = JHTML::_('select.option', '0', JText::_('NONE'));
$htmlOptions[] = JHTML::_('select.option', '1', JText::_('DAILY'));
$htmlOptions[] = JHTML::_('select.option', '7', JText::_('WEEKLY'));
$htmlOptions[] = JHTML::_('select.option', '14', JText::_('BIWEEKLY'));
$htmlOptions[] = JHTML::_('select.option', '30', JText::_('MONTHLY'));
You can either comment out the first line to completely remove the none option, or you can move it lower in the list. I do not know if there are any side effects to doing so, however.