ATC using squawk Code instead of Tail #??

[dueguard1]

Had the chance of getting a birds eye view of Rwy 4 at College of Aeronautics at Laguardia this morning.................Can someone tell me why Tower calls the aircraft by their squawk code instead of their tail number ?

 

[JetPilot_Mike]

Were you on MS Flight Simulator or something?

The only times squaks are broadcast are:
1)Getting them from clearance delivery (or varifying from PDC)
2)When ATC wants to change it enroute
3)When you takeoff with the wrong number entered
4)When ATC is confused about what target you are

It must have been one of those things that you heard.

 

[chperplt]

Could it be their flight number??????