What scope would be set for a Custom Dimension that reports membership status for a customer rewards program?

Custom dimensions and custom metrics are like default dimensions and metrics in your Analytics account, except you create them yourself. You can use them to collect and analyze data that Analytics doesn't automatically track. User-level scope allows you to conveniently group all of a user's component sessions and hits by a single value. It is ideal for values that don't change often for a particular user. Tip: Note that although this same functionality could be achieved with hit or session-level scope, user-level scope provides the most convenient solution with the least amount of code.