Ok, don't get mad, but I really don't like kids blowing bubbles in line. Maybe that's not what you're refering to?
Several years ago, while waiting in line, a couple of kids were blowing bubbles. The bubble were NOT going up, just over. Well, you can guess it... one burst in my DS3 face and he got bubbles in his eye. He cried, we dealt with it, but it really was unfortunate.
I also have to say that there were many other parents in line who were NOT happy about the bubbles at all. While we weren't rude, I have to warn you that others were pretty "snippy" about it.
One night time alternative is to buy cheap glow sticks. We buy ours at illuminationz.com. They are cheap enough that your kids can share them with other kids around them (like waiting for fantasmic, or fireworks, or parade). We did this and it was really fun and started conversations with other kids. But, of course, it only works after dark.