So did you sing along? I love it when audience members do that.
Umm... No I did not. But my fingers did move along every now and then.
Although, I do have to say I was a bit put off by some of the audience members who condescendingly "sssshhhhh'd" some people when they began applauding after his first Schubert song. Yes, it's polite and tradition to wait to applaud until after the whole grouping has been sung, but I really detected some venom in some of those "ssssshhhh's". -Besides, he wasn't singing a particular song cycle of Schubert's, just some selected songs.
...And then during the Hahn cycle in the second half, some people applauded after a particular beautiful rendition of "La Barcheta" ("The Little Boat"). -Each section ended with an extended "Ah...." that he just kept spinning out, note after note - no breath after no breath! Well, he acknowledged the applause, and even said, "Yes, I know it's hard to resist."

*He also inadvertently started one of the songs off with the wrong verse... So, after a quick wave of his hands to his accompanist, "Oh, let's start this one again." Very endearing.