I think the GDC should announce that he's getting the Lifetime Achievement. Schedule it for the end.
Then at the end, they should state, "Well, due to our altered schedule, we didn't have time to complete the Lifetime Achievement Award in time for today's meetings. Next year, we'll include it with the sequel to this conference and, trust me, chaps, this is going to be bloody awesome when it's included in the sequel! Peter, you'll be so happy that we waited for the next release instead of doing what we said and getting it done in time for this one!"
Because that's the kind of achievement he deserves. Lifetime achievement indicates that he's done awesome things during his entire lifetime. He had a period there where he was doing great things. That hasn't been true for at least ten years now, starting with his Lyinghead days on Black & White, its sequel, and then moving right on through his Fable years.
He's been living off what he did years ago for many years now. This award's just another case in point. Give it to someone more deserving. Like anyone. Excluding GRIN.