Being looked at while on a date?

I never go on dates usually I just have my random hook up, but while I made an exception for this girl I thought it would be cute to bring her out for ice cream has the night died down. Before we even got of the car we got stared down by two girls who wouldn't even look away if I looked right at them. I ask her if they were starring at us and she agreed. I was wondering why they wern't looking away? If anyone could tell