I live in Romania, and as you might imagine, we have our fair share of beggars (very few of whom are actually poor). Normally, they are easy to deal with: ignore or say you don't have money, and walk away. But as of late, I've experienced imposing beggars who come up to your car in traffic, while you're stopped at a red light, and offer to wash your windshield in exchange for some change. Under normal circumstances, this isn't an issue; they're working for their money by offering a service that some people want. However, often times, like today, the following happens:

I was at a red light, and this guy comes up to my car and I see he's getting ready to spray my windshield. I tell him "I'm don't want my windshield washed" and he replies that he's going to wash it anyways. I yell at him again stating that I won't want his service, and he sprays it and starts cleaning the windshield. At this point I get out of my car and and start walking towards him, and he stops. He then starts begging me for some change. I get back into my car and he comes up to my window begging saying he's hungry. At this point I was pissed as hell, but didn't want to risk an assault charge, looked in my wallet, and told him I don't have any money. Only at this point did he back off.

What would be the best way to handle this situation, especially when your girlfriend is sitting in the passenger seat?