During a discussion today I was informed that the Customer is_active flag doesn't actually do anything.
This is a unique flag, like the customer email address, in that it's not an EAV attribute. Instead, it is a column in the customer_entity table.
I tried setting the flag to 0 for a test customer, but am still able to login. All other functionality seems to work normally.
Is this flag provided as a convenience to developers? Is it intended for some future purpose? What, if anything, does is_active do?
Edit: Here's a related stack overflow: https://stackoverflow.com/questions/3617832/disable-customer-in-magento