Having a good idea is one thing -- selling that idea is another.
Rule #1 - If you go into a meeting and expect to present an idea without having sold it to others beforehand and your idea is rejected, you are doing it wrong.
Rule #2 - If you want your idea to be accepted, make sure you couch your sales pitch as if you got the idea from the leader.
For example, before telling others at a general band meeting that the second slot is best, talk to other band members ahead of time and say something like, "Josh, I was talking to Ben (the band leader) and he was telling me that you see a 20% decrease in the audience for the third slot. The more I think about it, the more I think that Ben is onto something. We might be better off with the second slot. What do you think?"
Then, at the general meeting, say something like, "Ben pointed out to me that the third slot gets a 20% drop in attendance. We may be better off with the second slot. What do you think Josh?"
At the end of the day, it doesn't matter who gets the credit for a good idea. All that matters is that the band, as a whole, is making good decisions and becoming more successful.