Don't ring twice and it's alright

I thought I would up date you on some young peoples cultural codes. Tim tells me that when he and his friends are riding around on buses they spend the time checking out girls who get on the bus at the various stops. He told me that they listen out for the Oyster Card beep because (and who knew) the adult card beeps once and the child card beeps twice. He said when a cute girl of indescrimate age hops aboard they are all ears because they have an off limits policy on double beepers! How utterly responsible - it's hard to believe we are related at times.