Tab through, press enter on a 'Skip block' link (at present a small white rectangle with dotted outline) and the browser seems to go to the next block/course content. However, tab again and you're still at the same link - you haven't skipped at all.

The fix will be in, theme/standard/styles_layout.css - code modified to,

.skip-block-to {
display: block;
height: 1px;
}

(Thanks to Bim Egan's Techshare presentation,
http://www.rnib.org.uk/wacblog/category/articles/too-much-accessibility/)