Keep in mind that each group is there for three days and plays three concerts a day, so there are nine chances to see any particular act. That tends to make the concerts less crowded. We've been to WDW several times during the Flower and Garden festival, and I don't think we've ever felt the need to stand in line before a concert. We can generally just walk in and find a seat shortly before the show starts. I'm not saying that the shows don't ever fill up to capacity - I'm sure some of them do. But it isn't the norm. If you absolutely have to have a front row seat for your favorite group, then by all means it's worth your while to get in line an hour or more early. But if you just want to hear the music and don't care where you sit, you can probably get in just before showtime. As a previous poster said, you can hear the acts just as well if you stand in the back or sit at the outdoor tables outside the American Adventure counter service place (whose name I always forget).
