Thank goodness you didn't pause for the drink break!
I haven't fallen into this problem, mainly because I realised early enough that I had to pay attention to film classifications when DD, at about 4-5, found a U cartoon (Lady and the Tramp II) almost too scary to sit through.
So I'm now pondering her request to get the new Harry Potter as soon as its out on DVD - she's 10.5 now, I think its a 12A. Suppose I could get it and watch it first while she's at school...
DD does get exposed to a lot of sex and violence on TV - some bad cases of infanticide... yes, she loves Spring/AutumnWatch