I'm not sure where you are from but if you buy the uno in some parts of europe the front brake is included because it's mandatory by law. I myself would keep the front brake on for sure! happened to me once while I fiddled around with the rear cog on my tern link uno. The smaller cog didn't have as much of an off set and i didn't fix it with spacers yet so i was just going on some good speed before my chain self derailled! good thing I had my front brakes. Another time my buddy who rides a dahon mu uno had his chain fall off while going downhill towards a 4 way stop sign intersection! but luckily he did have a front brake and slammed on it! Those two incidents was enough for me to not just rely on that single rear coaster brake for the sake of having a clean handlebar.