Null alt tags for decorative images - Technique H67

I am having real problems with a client who insist that certain images are decorative and can therefore be given a null alt tag as per H67. I can accept that a squiggly line or fancy text box border is decorative, but not a largish picture of a building (no particular building, just a museum type facade).
I really think that it is time to remove H67 as a technique, either a non-text item such as an image should have a text equivalent, or it should not be imported by HTML but be treated as styling and imported via CSS so that it is totally ignored by screen readers etc. This way there is no need for subjective discussions.

Any thoughts ?
Richard
Richard Warren
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