Holy smokes that would be tough, darn near impossible, for DT to pull off, unless the requested set was decided a few weeks before the gig or something...
With a band like Metallica, not only are the songs not as challenging to play, but they have their "hits" that they probably assume people will pick. Looking quickly at the Metallica by request sets, most of those songs are songs they usually play anyway. With DT, who knows what songs would be selected, as they don't really have "hit" songs.