Can't get user_delete_submit function to fire

Hi,
For some reason when I'm using this, clicking on the Delete button just fires user_delete in user.module, so the user is deleted but user nodes aren't.
The form_alter hook is working because the confirm page with deletion options is show, and if I tweak the option text the changes show on the page. But the #submit value doesn't seem to work.
I also noticed that there is no form['uid'] value defined, though this appears to be a different issue.
Logging statements, echo statements, etc. in user_delete_submit are never called.
Any ideas?
Thanks.