I"m sorry Todd but your comparison to an inert physical cane to a dog capable of maiming or killing a human being is ridiculous.  
If you have a trained seeing eye guide dog, you've spent thousands of dollars in purchasing the animal then being trained as handler 'team' before you take possession.   I doubt your family would have a problem with such an animal.   It is not an easy thing for a trainer to fully prepare a dog and partner for the public.   Lot's of dogs that start training, fail, as they should.