Fixed gear bikes stop better than bikes with no brakes as you can skid just as well as you can with a coaster brake... with some practice.

With no brakes you can put a foot down or "ted shred" and wear out your running shoes in lieu of a brake when you jam your foot on the rear wheel.

At 6 mph you aren't going much faster than a brisk walk so jumping off does not pose a lot of risk.

I see the same thing here among the homeless as we do outreach programs to help them with their bikes and many come in lacking brakes.