I've got to be honest and admit I've never heard of Katy Perry, don't know her music and don't really care, but I realise that a lot of youngsters will.
Perry has caused outrage by posing for publicity snaps while brandishing a flick-knife and this has upset anti-knife campaigners, understandably - but this fits in very well with the marketing belief that there is no such thing as bad publicity. Many "celebrities" have done very well out of doing stupid, illegal or offensive things.
Mediocre chefs become stars just by uttering the eff word loudly and often on TV. Rather plain models boost their careers by allowing themselves to be photographed snorting coke and we've already seen how other rather talentless pop wannabees can improve their profile by getting themselves arrested repeatedly.
This latest stunt is deliberate and calculated. Perry may not even be aware of the outrage she is causing - although that is unlikely - but the PR men will be only too aware and will be rubbing their hands with glee at the publicity it is getting. The best thing to do is to ignore her - and by that I mean we should not allow her into the country, should not play her music on radio or show her performances on TV.
Only when doing stupid, illegal or offensive things causes harm to someones career or personal circumstances will they stop doing it.