That is a true video, in NYC or another large town where pretty much everyone is anonymous and interfering with someone likely will bring more trouble than not. However in suburban areas or areas that are privately owned where people generally know what's accepted and normal versus out of the ordinary, someone plugging an angle iron in a nearby streetlight base and going to town on a bike will be quickly intercepted by either a security guard or the local police.

Also, due to the carnage of the past week, I'm pretty sure people will be more aware of anything out of the ordinary.

To sum up... in big cities, people can have at it with power tools in broad daylight... other parts of the country, 15-30 seconds with the iron out may land the person at the business end of some pointed questions.