Might I add that you do not have to get a username or password or give an email address to participate in the submissions. Therefore you don't even have to be in Queensland. I'm sure they will log IPs to prevent double-dipping, but apart from that, you're anonymous.
Therefore, by offering your support, it might lead to a wider acceptance of the lane filtering, even to the extent it becomes Australia-wide.
I know not everyone thinks it's a good idea. In that case, just ignore the first part and have your say on helmets and riding position (i.e. hands and feet on the controls at all times).
You don't need to speak out against lane filtering. I'm sure there will be plenty of car drivers doing that for you- the ones who can't stand seeing someone else moving through the gridlock when they too, could buy a bike and escape the cage.