I (an American man) would probably have asked if you needed help but would never have called the cops. Long road trips are common in the US, so if someone is sitting in a car for a while my first reaction is "Maybe they're lost and the battery on their phone ran out. Should I ask if they need help with directions?"
Yeah, but this was in the city center, albeit on a pretty quiet street (surrounded by embassies and various government buildings). She seemed to want us gone more than helping us. I don't blame her, 3 people just sitting, talking in an Opel Omega is pretty suspicious by western standards :D
That behavior is not not (double negative intended) stereotypical for the kind of American woman who have the money to be able to travel internationally.
We had some business with an army officer and he was busy with something so we had to wait.
About 20 minutes after we parked, an American woman comes and asks us what we're doing here and whether we need help.
That was weird because no one in our country does this, everyone minds their own business.
She did accept my explanation, but I had a feeling if we didn't move from there 10 minutes later she would've called the police on us :D