This question was posted in response to the following article: http://help.adobe.com/en_US/ColdFusion/10.0/Developing/WSc3ff6d0ea77859461172e0811cbec22c2 4-7c48.html
Under Accessing and changing session variables,
type="readOnly" should be sufficient.
<cflock timeout=20 scope="Session" type="Exclusive">
<cfoutput>
Your shopping cart has #Session.ShoppingCartItems# items.
</cfoutput>
</cflock>