Yeah, I think the bigger danger is - in the event of a Yes vote - what the actual legislation will be. The last bill went to a Senate Select Committee and was full of exemptions, not just for religious reasons but for "conscientious belief", which would basically introduce new, legalised discrimination against LGBTI people. The Committee, of course, called them out on all these issues.
So basically I suspect they will put forward another unpalatable bill to further delay its introduction as long as possible.
This being different to the Republic referendum, where they put the unpalatable question to the public. They can't get away with that this time but I bet they'll do whatever they can to delay it.