If I had been tanking I probably would have been irked but no more than when I lose rolls to dps plate wearers. But I would not have complained – if you wear a shield you have every right to roll on them (much more so, I would argue, than the plate dps’ers who are not wearing a shield in the run).
Also, by the way, the shield dropped by Tinkerer Gizlock (Gizlock’s Hypertech Buckler, +10 intellect, +5 stam, +4mp5) was a big upgrade for me as a protection warrior due to the armor and block value. So I hope you don’t mind if we warriors roll on that.