In Australian media the VLF people at the facility near Learmonth have been sort of quoted as saying "we've been there a bloody long time and no aircraft operator has complained, and anyway we are not the only VLF facility located near commercial airways, and none of them have been cited either."
Methinks the ATSB put that reference, plus the one to passenger operated devices, into the report in order to placate who knows who.
They will look at both because they are thorough professionals, but clearly the onboard gear is the prime suspect, and greatest worry.