When you update contact information you also need to check the Opt-in
You always require an opt-in or even a double opt-in when enrolling members into a customer database. Sometimes you might miss out on a opt-in or someone has done an opt-out. It is always possible to update the contact information and then you might need an opt-in as well.
The legal concerns are different in different parts of the world. Some states in the US and some countries in Europe have different regulations that might be worth a second look with legal when looking to update contact information and updating the opt-in for example. Since we make it so easy for members to identify themselves at POS we utilize this opportunity to update contact information where gaps in the database exist.