As an airline pilot, and someone in the UAV/RPA industry, I don't think there will be a sudden safety risk come September due to the new laws. There's still a bit for CASA to define, but we've tried or explain the rule changes here:
http://www.aerialhotshots.com.au/uav-training/new-laws-sub2kg-rpa/
Just because someone can gain financially with a small drone doesn't mean we're more likely to collide with them. Guys trying to make money without a operator's certificate will have to conform to standard operating conditions, which will limit their height and operations near airports. They will also have to register with CASA. Yes, there will be rouges, but I doubt they're going to be at 3000 feet on the approach path. Even if one is up there, it is a big sky.
The ones you have to worry about are the You Tube heroes trying to fly as high as possible or push the limits. These guys exist anyway, and won't suddenly increase in numbers just because of the new laws.
Birds still pose a far greater risk, and we're not shooting them out of the sky.
The new rules are more likely to affect some smaller UAV operators due to lost business - don't make this a safety argument.