I think the concern was the unexpected turn after takeoff; had that happened to the right during SODPROPS
Sydney Tower ATCs have been doing compromised simulator sessions in the Melbourne Simulator using the 360º sim. This and other scenarios are discussed.
SODPROPS in Sydney uses 3000ft cloud base which is above the 2500ft specified in AIP.
The only occurrence that I am aware of involving anything like what has been suggested (turning right from RWY 16L) involved an Ansett A320 which tracked 155 rather than L125. As I understand the aircraft was flown by very senior pilots who only flew the minimum number of sectors to remain valid.
http://http://atsb.gov.au/publications/investigation_reports/1997/aair/aair199700052.aspx
Departing aircraft are given a directed frequency transfer so this means that any identified non-compliance (not turning, drifting towards the RWY 34L approach) can be rectified prior to the transfer to Departures.
I encourage the use of the KEVIN or ABBEY SID during SODPROPS rather than use the SYDNEY SIX as I think this reduces the chance of someone dialling in 155 or even 170.