Whats the go!!!!! A hoist or more?

Look at the pictures below and tell me what you think could be happening.

There were 7 police cars

One riot squad car, black not white though :)

An undercover cop car

and 10 motorcycle police.

One more clue for you, there was a medium rigid truck with a red tarp on it.

can you guess?

well can you????

I was in the city today and one of the docks was full on Phillip street, so my offsider and I were out of the truck and on the footpath waiting. We heard a siren and thought it was a motorcyle ambo, but a cop came screaming down the street and pulled up in the intersection. A few seconds later there were more hitting all the intersections, I was curious ans then all these cop cars started to show up, marked and also unmarked.

My first thoughts and quite a few after were of a siege or a bank hoist, my thought seemed to be confirmed when the riot squad armoured vehicle showed up as well. I don't think I'd seen so many police vehicles in one place, the whole road was shut down, and then it was pointed out to me that there was a truck with just a tarp up in the midst of the action. One of the other couriers also waiting told us it happens abit and they were moving gold bars into one of the banks and so they get an escort all the way from the airport and all the intersections get shut down on the way through.

Well that was a part of my exciting day, so did anyone guess what was happening?