We like to watch any parade from a tree "island" near the Frontierland side of the entrance to the Liberty Belle Riverboat. There's a low stone wall to sit on, and a rail fence to lean against. If you play your cards right, there's a point where the tape line comes so close to the wall that no one will dare try to stand in front of you. But it's not the best place to watch the fireworks.
We've never been told by a CM not to sit on the wall, but don't stand on it!
On 12/30 the CM's were overwhelmed trying to keep people off of the enclosed part of the 'island'. People, mostly teenagers who were there with there parents, were climbing over the fence, trampling the flowers, and trying to climb the trees!
I'm amazed sometimes at what people let their kids get away with.