Or a diligent resetter of expectations. And HTML star should be able to effectively argue against that sort of requirement. Otherwise, what are you paying him for? Markup monkeys are dime a dozen, and there's an A List Apart Sliding Doors article those code monkeys can just follow.
I'd expect more from an HTML star than just knowing how we did rounded corners before border-radius. I'd expect leadership, and standing for correctness.
In both Yahoo and Amazon we succeeded in pushing back against rounded corners in browsers that don't support border-radius. Because that's the pragmatic thing to do.
Browser compatibility doesn't mean pixel-exact layouts, it means that the core objectives of the site are functioning in a customer-supportive way.
Rarely do customers bring up the site in two browsers side-by-side and decide not to buy because the website wasn't identical in both.