hmmm... when was the last time you tried? Because the last time I was there (sometime in November last year), free access was disabled in Novena Square, and we could only connect via Burger King (which at that time was undergoing trial and thus free).
Last tried United Square was in early Jan 03. No problem. A good spot is the food court at the table around the fish tank near the entrance of the food court. I frequent there to wait for my kid attending tution class.
For Novena Square, it was late last year quite some time already.
I believe both are under UOL hence if one is free the other should???