Ya cant see your front wheel on a SWB. But OTOH...
I took the LAB 'Road I' course a few years back. One exercise we did was for avoidance. We put a sponge (fake rock) on the driving course, and the object was to put the front wheel around one side of it and the back wheel around the other side of it. There were only two cyclists who could do it successfully and consistently: a TourEasy rider and me, on my V-Rex. One of the upright riders who couldn't do it had completed riding from Fairbanks Alaska to the Keys in Florida. Conclusion: I don't think it's a serious issue, because you 'know' where your front wheel is.