OK, so for IE8 users return a single page AJAX app instead as a variant of what's already done with Instant. Still no referrers but no POST warning messages (which, BTW, have to be one of the most annoying things about ASP.Net web forms - postback was a boneheaded design decision from someone who didn't understand HTTP.)
Topic drift: but I'm convinced that ASP.NET postback was a very deliberate design decision from someone who perfectly understood HTTP - and is intentionally obscuring HTTP in order to keep programmers and implementers ignorant of it and dependent on the Microsoft ecosystem.
