This may be naive, but that sounds like a good use case for a head-mounted collision-avoidance system (like the ones in self-driving cars). I bet you could fit such a thing in a fairly light-weight headband nowadays.
I suppose your solution would work as a stopgap, but it seems like poor design to make people adapt to human-made environments rather than building the environments in a way that works for everyone.
One problem with the "just install a railing" approach is that the environment changes. New stuff gets built. Temporary obstacles appear where there were none before. Not all obstacles are human-made (think about walking through the woods -- there will be no railings there, to be sure).
Another problem with it is that the person who benefits (the blind person) is not the same person as the one who must be relied on to alleviate the problem and foot the bill.
Also, why is wearing the headgear "forcing" while using a cane is not? I don't think anyone's being "forced" to do anything in either situation.
Ideally you'd have "defense in depth" such that your head-mounted collision avoidance system is just a fallback, but honestly it's one of those things where it would be best to take it into your own hands if possible.