I'm looking to remove old quotes from the database via a Magento shell script, and I see `enterprise_customer_sales_flat_quote` and `enterprise_customer_sales_flat_quote_address` whose purpose is unclear to me. These are don't have any key constraint on them to the native Mage tables. 

In the `Enterprise_Customer` module, under which the models for these tables are, there is not much responsible code. What are these for, and are they safe to remove along with the "associated" `sales_flat_quote/_address` records? ("associated" because there is no formal constraint but they seem to have the same `entity_id`s.