That is a legal requirement

When a client / colleague etc states that an action / feature / requirement has to be done / met for legal / regulatory reasons in a country always (politely) ask for the actual legal text / statute that states that what they are asking for is required. Possibly it is actual a legal / regulatory requirement but also it may just be someone’s opinion of a legal / regulatory requirement or they have a desire that they do not want to pay for so they state that it is required for legal reasons. There is no harm in asking clarifying questions before committing time and resources.