Automatic Alt Text Generation

I've made a couple of suggestions for inclusion in the authoring tool guidelines as we discussed in the recent conference call. Please let me know if you have any comments.
 
HTML tools should NOT generate 'placeholder' ALT text but should leave the Alt text blank (ALT="") or not generate the Alt attribute. Placeholder text could be generated by the tool to let the user know that some text should be added. Examples of this include "Alt text here" or "Place Alt text here". If placeholder text is generated then accessibility checking tools will only see that there is Alt text and assume the element is accessible. This should be a priority 1 item.
 
HTML tools should generate default Alt text with caution. If default text is generated then the user must be offered the option of changing the text. Priority 2?

Chris