1. When an international pop star takes part in a photoshoot, it has to be arranged some time in advance. Not only does the photographer have to be booked, but so does the stylist, make up person, hairdesser, lighting tech, lighting rig, phtographer's assistant, catering etc etc.
2. In addition to this, security has to be in place. Rihanna cannot just pop out with an entourage like that without physical security.
3. After spending all that money, booking the photographer, security, assistants, lighting engineer, publicist, catering...what are the chances that not a single person in the organisation would think, "Perhaps we should ask permission?"
So after getting permission, her people DELIBERATELY took photos which they knew would've gotten them into trouble.
And bish bash bosh - a nice big old article in the papers for a bit of free publicity.
Rihanna is simply doing what Madonna has been doing for about 85 years...
Oh, one last thing - the photo of her sitting down, looking directly left...how is it possible for a woman to be THAT beautiful without spontaneously combusting???