I think Vettel probably has a great chance of heading Webber off into T4 - leading off the start line isn't exactly a good proposition around Korea as it leaves the other guy free in your slipstream for a good 2 kilometers total.
Regarding team orders - not a chance Mark will listen. He will develop radio problems, most likely!
However I do believe Mark might be fooled into doing a team order by coded messages he can't disprove. If they told him to manage tyres or brakes, he'd just go "f*ck off." HOWEVER - if RBR say to him, "Mark, your gearbox is running extremely hot, there might be a problem. We need you to shortshift until we can see the problem." or "Mark, your brakes are about to go. Be careful on the brakes." then I think that could be a possible.
remember Brazil 2010? Mark was told, "Mark, gearbox oil is running hot. You need 3 seconds of clear air to manage the temperatures."