I could, and did, ring my bell continuously at times (bells are great to have for several reasons) but there were always more than a few who pulled to the left abruptly at 12 mph, just begging someone to take them out. To them, anyone going over 14 mph is a "racer" and of course going fast was the real problem, because "it's a tour, not a race." You'll see that argument a lot in the RAGBRAI forum. Being clueless might be excusable if you're alone on a MUP, but not when you're sharing the road with 15000 other cyclists, all trying to do a speed they consider 'normal.' Even when I was cruising at 25 mph, I
always checked behind me before pulling out to the left. After all, Lance was on the ride, somewhere behind me.
I think about 30% of the cyclists on RAGBRAI have less than 100 miles under their belts for the year.