I go to seminars to critically judge the teacher and constantly say "Oh I KNEW THAT ALREADY", with my face all screwed up and lots of "hhrrrummphh" sounds throughout the instruction. Of course this is all done covertly, as I also try my best to be the star pupil in front of the teacher and Typically, I will pick a weaker person to practice with and USE MY OWN TECHNIQUES aggressively on them instead of the ones being taught.
As part of my seminar preparation, I will also spend some time beforehand, digging up whatever dirt I can on the instructor/teacher, which I spread around quietly to other more gullible participants. Also I will constantly make value judgements on the teachers abilities (behind thier back).
After the seminar, I will incorporate what ever I learnt secretly, and act towards everyone else as if I already knew it all beforehand.