When you are driving home at night and see a bum-looking guy kneeling next to a bike trying to get rid of the lock... what do you do?

I turned the car around and stopped by, rolled the window down and politely required a brief explanation on what he is doing. In reality, I yelled the f-word in that question, as the whole thing seemed kind of self explanatory. I did not get him off guard.. He yelled back that it was his, he just lost the keys cause he is drunk - he did not even look up.
I took my best shot, and yelled back that I just happen to know a guy who lives in this house and has a white bike, and I hope that mr Bum doesn't mind but I will give him a call now.. and I pretended to call someone.

He did look up. And than looked back at the bike and kept harassing the lock and murmured something like he doesn't care.

What is uncomfortable in the situation is that he either did not get what I said, or did not believe it, and there is a highly unlikely but still possible answer: the bike was his.

I do not have the right to ask him to prove it, and if it was his, while he had no way on earth to do so even he wanted to.

Take away: drive high voltage elecrtricity in your bike when you park it. When you get back, you might find people lying around it, but hey, they should have minded their own business, or kept the fucking dog away the walked, or thieves. Don't worry the ambulance crew on the top of the pile, just remember: in war, there are casualties. They really should have taken the sign seriously you wrote in Hutu language.