Use of absolute font sizes breaks WCAG 2.0

Zen's block-editing.css uses an absolute font size. Could we use something like:

  div.block.with-block-editing div.edit
  {
    display: none;
    position: absolute;
    right: 0;
    top: 0;
    z-index: 40;
    border: 1px solid #eee;
    padding: 0 2px;
    font-size: 0.9em;
    background-color: #fff;
  }

So that it doesn't break http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/C14

when validating for WCAG 2.0 through - http://www.tawdis.net

Thanks.