I didn't mean to imply that the issue is constrained to Telerik RadControls. It appears to be a limitation of the Ajax framework. Ok, that doesn't mean your examples shouldn't have warnings associated with them to prevent developers from wasting time.
Anyhow, I have seen the suggested use of scriptblocks and I have found them not to work. I am unable to attach a project to this forum post, so I have opened a ticket.