The gambit that Marvin used to get in with Anna was actually a social engineering technique that intelligence officers used to use during the Cold War to recruit female assets. It was called "Is this guy bothering you?" However, to maximize the effectiveness, the inciting agent was usually busted like Marvin and the recruiting officer was the handsome and charming one. Because the point wasn't getting into their pants (always a bonus) but rather getting to their secrets. I think that the ruse was ill-conceived and did more to demonstrate Marvin's inflated opinion of himself than it did to influence Anna's decisions. Anything Anna did in the car, she was going to do anyway, because Anna isn't naive. She is a manipulative narcissist, and narcissistic people use everything at their disposal, including sex, to influence people to do what they want. So in the end, the gambit was extraordinarily pointless. Marvin probably doesn't realize this, but we do because we are friends with the spiders that live in Anna's broken brain. So, congratulations to all the folks rightly pointing out that the entire scene was stupid. Here is your no-prize.