I've been using the technique described in this post to remove the caption and description fields in the uploads modal window, thus eliminating unused clutter for users. Since the title field is already required when uploading images in WordPress, it's easiest for my users to dispense with the alt field altogether and just pull the alt text from the title field when displaying images on a website.
From what I'm seeing in the media.php file, I should be able to unset the alt field by adding this to my function:
unset($form_fields['image_alt']);, but it's not working. Any suggestions as to what I might be doing wrong?