We have a form in which customers can sign-up for multiple smartlists (two actually...)
The problem is, that if customers previously has signed up for e.g. Smartlist 2, and check the checkbox for smartlist 1, but does not check the box for smartlist 2, they actually sign off smartlist 2 in the database.
Is there a way to avoid this? Like, "if not checked, send no value"?