I would equate it with any new member entering the dojo so if by numbers that equals an added risk or burden then mathematically that would be so but I say this for a different reason.
Firstly the disadvantage should be taken responsibility for ie: a blind person may need to orient himself with the surroundings first etc. Thereafter treated with the same respect as everyone else, no difference.
Secondly I don't hold to this people hitting each other with bokkens and falling into each other all the time or even on numerous occasions. When I witness this I am witnessing an ill disciplined dojo.
As I said before Martial arts teaches people they CAN. PC do gooders teach why they can't.
What is your view on the effect this may have on other students?
I also do not see why handicapped persons should not be able to practise (within their imposed boundaries). I would worry more about the student with back problems, weak set of knees. But still it will have effect on the group as a whole.