I'm working with a case where the text for the tab label is already HTML formatted. The TabStrip is bound to a DataSource object, allowing me to specify the text and value fields. However, I cannot specify whether the title is encoded or not.
Currently, the workaround is to use javascript to modify the HTML of the tab label after it has been rendered (http://dojo.telerik.com/UXuTE), but having a way to specify which data field to map to the encoded property would be much simpler (see above dojo for and example).