I'll just add one point that may be helpful. Some seniors may be concerned about issues related to their benefits under old age security, or their benefits in relation to medicare. With respect to OAS, once a person has lived in Canada as an adult for 20 years, residency ceases to be a factor in terms of their eligibility for OAS. They can decide to live anywhere they want in the world, as long as they've lived 20 years as an adult in Canada. Their pension then becomes fully portable wherever they wish to take it. Bill C-21 would be irrelevant to that.
With respect to medicare, because that is administered provincially, the information is shared only with federal authorities, not with provincial authorities.