I think you are getting a little confused as to the purpose of the Australian Transport Security Regulations. As it stands at the moment, all legislation pertaining to screening and ASIC compliance is in place for the protection of RPT flights.
As a private pilot wearing my ASIC, am I then allowed to walk up to the RPT aircraft?
You can try it but I would then expect a call from your local state or Fed police officer for a bit of a chat.
The ASIC only gives you access insofar as you have a lawful excuse for being airside. Having your 172 parked on the edge of the apron is not an excuse to be up close and personal with the RPT
Islander Jock, if the idea of the ASIC is to protect RPT, and yet the ASIC wearer is not allowed anywhere near the RPT - what then is the reason for private pilots to be required to have an ASIC ?