I used to have a fixie when I was 11. Hell, everyone I know did. We called 'em BMX bikes, or just dirt bikes. I'm pretty sure we had hand-brakes, too, but that's not a detail I remember. I do remember locking the rear wheel and skidding down hills...

Going without brakes is another story. I wound up riding next to someone on a fixie one day at the top of Queen Anne Hill, and we wound up going down the hill together. At the bottom - we're talking 15 % grades - he looked at me and said "I don't think I could have stopped if I wanted." I told him that's why I had disc brakes. ( Although I have to admit I stepped down to regular ones. ) I can't imagine why anyone would go brakeless in an urban area.

In before the lock.