I would take issue with your observsation that Ms Rowling is a 'rather over-rated celebirty' - in my experience Ms. Rowling has done nothing what ever to court publicity for herself personally, and since the cult of 'celebrity' demands an individual is famous for simply being recognisable for a short time, then Ms. Rowking failes on both counts - she is a massively successfaul author, and most people wouldn't recognise her if they fell over her.
As to the by-passing of regulations - I haven't seen the news story, but it wold appear that the enforcement of several draconian and pointless restrictions are to be lifted now anyway, so she obvbiously thought it worth making a stand to protect the privacy of her work.
I would suggest that anyone making a similar stand under similar circumstances would have received a similar reaction - the airlines have all calmed down now, and the ability to carry on 'unsuitable' hand luggage will inevitably be restored.