For those of you who are looking to gather the courage to go out in a diaper, let me offer this encouragement.
I do not usually ride a bike in a diaper, but during cold weather I've done it a few times. Last week I came home from work in a slightly wet bambino and pulled on (long) cycling tights over it and rode the racing bike for a 16 mile spin. I suppose I would have turned around had chafing been an issue, but it wasn't. I did choose a long jersey, then went to a shorter one just for the extra fun of risking a bit of white appearing over the tight in the back. It probably did show a sliver, but not much. Standing in front of a mirror, the front looked like a diaper, but the back didn't look too out of place. I have always figured that a diaper under a cycling tight looks often like a padded short under it, which I do all the time. And of course, spectators can't see your front while you are riding. Yay for bambino, because the diaper did not shred or bunch up or anything bad.
A few days later I went on a bike errand to pay a bill at the doctors' office (half mile away). Problem was I had just wet the thing and (in regular clothes) I was down the end of my street when it was obvious I had pressed the wetness out of it and onto my gray Dockers. I went ahead with the errand. A car of college age boys passed me but did not seem to take any notice. The bolder step was to change at home into a Dry 24-7 (medium) and go out on my 18 mile loop. (I live in a small town which affords easy access to quite rural roads. It is not like i am riding in Manhattan.) This time I was anticipating a bit more chafing, since these babies are considerably thicker than bambinos. But nope. Yay for Dry 24-7, my favorite diaper. Another concern was that I was a bit farther from the cleats and so my legs were a bit more extended. A strain on the ligaments is always possible when the geometry changes - and one's muscles are dialed into a specific bike fit.
So should you give this a try? While definitely not for everyone, if you are adventurous, I say go for it. You can always turn around if you feel chafing may be a problem. It is kind of a fun kick to be riding around in a didee. I suppose I should add that my hinie is used to long rides - I have done double century rides nearly every year for the past 18 (200 miles in one day) and today was the first 100 miler this year. (It was without diapers. I am not THAT nutty.) I don't think I would try diapers for anything beyond an hour's ride.