How to force the customer to choose “Yes” in an “Yes/No” attribute?

Question

I have a customer attribute which ask the customer to agree our Terms of Services with attribute code tos. How can I reject a customer registration when tos is chose No? And, how can I display the error message like You must agree with our TOS?

NOTE: There are no Checkbox on Input Type at Customer Attribute. I'm using Enterprise Edition so I can create customer attributes without coding.

Answer 1

To achieve this you can create a custom select type attribute with only one option Yes.