alexnharvey wrote:Slowster, i think he wasn't riding no hands for the accident but rather one handed. I would also guess that he was caught out by some difference in handling, likely worsened by haste.)
Apologies, I misread your original post.
Reading it again, I can imagine another reason for him finding the handling so different and potentially less stable (for him). If he is used to the saddle being further back behind the bottom bracket than the set up on your bike, that would put more weight on his hands and thus on the handlebars. Removing one hand would then be likely to result in the handlebars turning under that weight, unless he had strong enough core muscles to stop that. Having drop bars with the hands further forward of and closer to the steering axis (due to the narrower width) than they might be on a flat barred bike, would probably exacerbate that effect.