So it would need to be fixed rear wheel to be safe? Fair enough, I am not familiar with this kind of bike. Having said that, even if it was fixed, if you had to stop suddenly surely you would grab the brake as well as stop peddling? So the momentum would still take you over the bars? In my view having a front brake and a free rear wheel must be a lot safer than a free front and fixed rear bike (i.e. no brakes) that I see a lot of on here.
Live and learn!
Most of us ride fixed on the front too, with at least 3 brakes.