Strange wifi behavior during clean install

[gbsh]

Can anyone explain this:

MacBook Pro Model 5.2 running 10.8 connected to secured wifi network.
Download Mavericks and create usb install.
Replace hard drive in MacBook with new unused SSD
Install Mavericks from usb

No issues installing, but during the install I notice that the wifi connection is on and connected to the wifi network!! How has this machine remembered the wifi key?
Surely the wifi key should have been stored in the old OS on the old hard drive which is sitting on the table next to me.

Anybody any ideas?

regards
Gary

 

[Bruno09]

How do you know that the machine was actually connected to the wifi network ??

4 grey bars do no mean that the machine is connected : it just "sees" a wifi network.

 

[squeakr]

It could have also had a self assigned IP and appeared to be connected. Would have had to look at the router and see if it actually was connected to tell for sure.

 

[gbsh]

Wifi icon in top right of screen, showing full signal and a tick in network list against network SSID name. I would have expected to see light gray bars indicating no valid network connection.

Regards
Gary

 

[Bruno09]

The wifi key is stored in Keychains.

I can not understand how such a thing is possible...

 

[gbsh]

Because this is a non-removable battery, and even though I powered the machine down before changing the drive, I wonder if some portion of memory is still active.
Only a thought, and even more interestingly, now I have Mavericks installed it can't connect to the network - wifi key required!

Regards
Gary