Keeping a clear distinction between markup and content by using case

Recently W3C has released its recommendations for MathML. Part of that recommendation was for keeping tags in lower case. The main rationale that I know of for doing this is that the page will compress better if more of it is in lower case. I do not find this as compelling a reason for making this a standard as that for ease of markup and page maintenance, besides uppercase has been standard practice so far and computers can easily manage both cases.

When I teach HTML I insist that my students type the tags in uppercase, so that it is clear when scanning a page which parts are markup and which are the actual content. I am not the only instructor to teach this, I have found a number of online sites and a number of reference books who also insist on such a markup style. For myself this comes from long experience in updating and fixing HTML pages. HTML editing programs can display markup in a different colour from markup, but not all authors will have access to this sort of software including blind and colour blind authors. I am afraid that W3C is planning on recommending the MathML format for all markup and I would like to see people urging them to reconsider.