OK this is proberly pretty random but i was watching Kerrang last night and Greenday - Jesus of surburbia video came on and according to what is blanked out and what isn't:
You can drink,
You can steal,
You can throw food around the supermarket,
You can have sex BUT
You can't smoke,
You can't bleed
and no one can have sharp objects.

Ok i can get that before the watershed parents don't want their kids seeing certain things that could ruin their young minds. Still you can see people smoking on the streets so why not on TV, you have proberly bled at least once in your life and anyone who has been in a kitchen/science lab/art lesson has seen a sharp object so what is the point!!
They're blanking out things everyone knows about and isn't illegal and letting them insinuate that doing illeagal stuff is alright.