I would like to be able to make olinks NOT hyperlink in certain formats when I can't be sure that the target will be available. I've implemented it in my customization layer by declaring the new param <xsl:param name="olink.hyperlink.external.docs" select="1"/> and then customizing <xsl:template name="make.olink.href"> from common/olink.xsl and html/chunk-common.xsl to change:
<xsl:if test="$olink.key != ''>
<xsl:if test="$olink.key != '' and ($current.docid = @targetdoc or $olink.hyperlink.external.docs != 0)">
That does the trick.