Yeah, I only go to shows to get laid so I don't really care much.

I'm sorry, but what Urban contributes to Music Banter utterly crushes your contribution. Like several said, if you disagree with Urban's statement then that's fine, to just poopoo anything in that manner accomplishes nothing. And I should know, I just did something like that yesterday to Goofle. We're all capable of stepping on our own wang now and then.

I think the artist should care because the fans are the ones who pay for and support their opportunity to perform live. And keep in mind, as originally posted, I'm not talking about bands who normally jam, or have a proclivity to spread out the songs somewhat (Dead, Matthews, Widespread, etc)- I'm talking about a band who had a hit song but no longer perform it as it was- for whatever reason. I know when I saw Floyd back in the day, I was stunned mid-show to realize that they sounded pretty spot-on to the recordings, and seemed to take great steps to ensure this. I think with the basic rock band, there is a difference in sound between live and recorded performances- that HAS to be accepted- but that isn't what I am speaking of- I am suggesting the total dismantling of a very familiar sound- If Zeppelin were to reunite, do a tour, and end the show with Stairway To Heaven but do it in a 1980's new wave band synth style, people would go nuts, and not in a good way. The Miller performance on The Jools show stood out to me because of the way that he kind of mailed in the vocals, improvising on the spot hopefully, as it wasn't great. The Forbert performance was a solo acoustic gig, so it's going to sound different, but for the most part, he was faithful to the originals, both lyrically and sonically, until he got to Romeo's Tune, where he played entirely different chords and an altered rhythm for the first 2-3 minutes- and it resulted in many not knowing what song he was playing, until he got to the chorus, which he did straight on.
I understand that an artist is going to improvise somewhat, and I get that playing the same song the same way for 30 years is boring-but isn't that part of the job- almost every job?

A band like Led Zeppelin wouldn't need your money on a reunion tour, so that wouldn't really matter in that example. Bob nailed it when he said that it's their property and their choice is the only one that matters. Some bands will regurgitate their old material live until they croak, but that doesn't invalidate those who choose not to.

Looking at you Rush...

I absolutely love it when a band takes risks, improvises, changes the arrangement or even genre of a song. This is in fact one of the most fun parts of a concert experience for me.
And fans usually seem to love it. Even if it isn't 100% successful, it's usually still incredibly entertaining and a fun surprise.

Yeah, there's nothing like being able to say "Oh wow! I was at [insert venue] when [insert band] did that amazing version of [insert song]!" knowing that they will probably never do it quite that way again. Makes it worth the price of admission.

I agree with that. But I also realize that is a viewpoint from a true fan, not the general music listener. The guy that owns the bootleg concert tapes, the guy who owns the entire catalog, the guy who can name everyone in the band. But a generalization that most fans like it isn't correct, IMO. Just because the 29,000 people bought a ticket to the arena show doesn't mean they are that level of fan- don't they have an expectation of hearing the song as they know it from the radio? While the deeper fans may relish that change of lyrics, the rest of the crowd (the majority of the crowd most times) may wonder what the heck is going on!

Spontaneity is the best part of live shows. If I want to hear the record, I can listen to the record.

Assuming that a band makes the decision to make changes, tough **** for that part of the audience, then. Not everyone in music has to abide by money making standards.