“You guys” is some easy vernacular for people of certain age groups (me included). But it should never be used to refer to the judges at oral argument.
A few years back, I had an oral argument at the Third District Court of Appeals in Lima, Ohio. The case in front of mine was a criminal suppression issue about whether the police appropriately entered the house without a warrant. Not having read the briefs, I thought the defendant’s counsel had a reasonable shot. But he kept saying “You guys should reverse the Trial Court’s decision,” and “You guys understand the binding precedent is….”
I watched the judges flinch slightly with each use. The argument eventually concluded, at which point the presiding judge said with a completely straight face, “The case has been submitted. We guys will issue a decision in due course.” I made eye contact with one of the other judges and we both burst out laughing.
A primary goal at oral argument is to appear competent in a way that gives your brief more credence. Referring to the judges in a casual way is going to cause you to be remembered for the wrong thing.