On behalf of all the support and banner based warriors, I feel this is necessary.
When you're out running wild in the world, and you see a warrior with anything but a greatsword, you may see him drop a banner of some kind. It may not matter much to you what each banner is capable of, but most everyone knows that attack #3 will give AoE swiftness. Knowing this, you may be tempted to take that banner off the ground to get a minute or two of spammable swiftness.
But you just took a much loved buff from a now very sad warrior. Please, leave the warrior his buff. You can pick up the banner and press the swiftness once, and then lay it down again if you're really desperate, but that banner is on a 2 minute cooldown, and that warrior has a build using those banners. As the only class with a buff that can be taken by allies, we trust that you'll be kind.
Don't make all warriors come to hate banners. Let the warriors trust the world again.