Obviously, the parent company has more rights than any of the subsidiary companies. When a subsidiary company is established in other countries, the parent company needs to examine the legislation of the country and should also adopt additional regulations that will not contradict the laws of both countries. That is the reason why demands made by the US Wal-Mart should be obeyed by the Wal-Mart in Canada. On the other hand, if Wal-Mart in Canada was given a permission to adopt its own regulations, the US parent company should not interfere into the policy of the Canadian daughter.
Yet, everything should be based on the regulations. Nevertheless, this issue can be considered as a gap in documentation; that is why the question should be answered in a different way. The only way out of this misunderstanding is to make negotiations between these companies. During the negotiations, the US Wal-Mart has to understand Wal-Mart Canada as the legislation in each state is the main regulator. Wal-Mart Canada, on the other hand, has to understand the Wal-Mart United States as it is the parent company and its policy is partly the policy for Wal-Mart Canada.
Suggested course of action is that Wal-Mart Canada should stop cooperation with Cuba. It should find a possibility to do it without breaking the law while taking into account the U.S. boycott towards Cuba by stressing the inconvenience of cooperating with Cuba. The reason is based on the relations of Wal-Marts in the United States and Canada: they are not equal companies with equal rights. That is the reason why the policy of Wal-Mart in Canada should not contradict the policy of Wal-Mart in the United States.
Surely, this way is not the best way out of current situation, but if we are talking about the relations between parent and daughter companies, it can be considered as the most suitable for both parties.