Rules of the lap

I recently heard about a friend of a friend who was mugged. It was a traumatic experience for her and one that I wouldn't wish on my worst enemy. Well, thats probably not really true. The detail that stuck in my mind though, was this - the mugger sat on her lap.
It was past ten in the night. Accompanied by a friend, sated post dinner, she sauntered to their car. As they got in, they were beset by a pair of villains who held knives to their respective necks. Villain1 poked the driver in the neck, insisted that the door be opened and valuables of every description be handed over to him. Villian2, not wanting to be outdone, replicated the rude thrust of his compatriot against the neck of our heroine. This is where things get strange. Once Villian2 had convinced our heroine that opening her door post haste was the wise thing to do, all considered, he then proceeded to get into the car and sit on her lap. Having done so, he did not attempt any lewd behaviour - well nothing lewder than the act of sitting on a stranger's lap. He just sat on her lap and robbed her blind. Having relieved her of all things that he considered valuable, Villian2, duly accompanied by his faithful companion Villian1, melted into the night to be heard from nevermore.
But he sat on her lap. I can't get over this teensy detail. Sitting on someone's lap is normally accompanied by a sense of surrender. The sitter is clearly less powerful, less in control, than the sittee. Here are activities not compatible with sitting on someones lap:
a. You can't shout at them
b. You can't ooze sarcasm and
c. You definitely should not steal from them, at knife point no less
Apart from being a tad evil, Villian2 was just plain rude.