Loath as I am to challenge the mighty cetacian, I am not so sure.
The condition report is everything and the permission to hang something may only have avoided problems during the tenancy – e.g. being ordered to take down the pictures and repair and paint the wall.
A different rental agent at the same firm could come in, see the holes, check the condition report from the handover and ping you for repairs.
Honesty may be the best policy here and just let them know you are leaving the holes in place for the next tenant. Or you could take your chances and hope your bond refund doesn’t get held up by a claim for damage to the wall.
Either way, unless you have written permission to drill holes and leave them after you have gone, you may be on a sticky wicket. Whale’s advice to contact tenants NSW or just look at the excellent fact sheets on their website (www.tenants.org.au) is spot on.