If that is the case we are going to have lock downs every day from now on, it is a good way to tie up police resources. 

Yes, and while the police are tied up with these lock downs, crims can have free reign in other areas of the city.

My daughter works in Sydney CBD as well. I am not going to panic, especially when a reported lockdown instance is not in the exact area she works in or lives in. Even when ithey are in lockdown they can still send texts and emails to let family/friends know what is going on, as she did in the recent  siege in December.