To be honest EZE customs are pretty relaxed in comparison to some places around the world. The only country my wife and I got pulled over for having something we shouldn't have was when entering the US from Canada.
My wife who is partial to having lemon in her tea had taken a lemon from the breakfast table that morning. She was caught at the customs inspection given a ticking off by the stern officer and had it taken off her.
She wasn't best pleased.