When the COPY INTO command is executed in Snowflake, it processes all files present in the specified stage that have not been ingested before or marked as already loaded. Since the user did not remove the original 10 files after the first load, running the same COPY INTO command again will result in all 20 files being processed. This means that the data from the original 10 files will be appended to the table again, along with the data from the new 10 files, potentially leading to duplicate records for the original data set.
References:
* Snowflake Documentation on Data Loading
* SnowPro Core Certification Study Guide

Snowflake recommends creating objects with a role that has the necessary privileges and is not overly permissive. SYSADMIN is typically used for managing system-level objects and operations. Creating objects with a custom role and granting this role to SYSADMIN allows for more granular control and adherence to the principle of least privilege. References: Based on best practices for database object ownership and role management.

Snowflake virtual warehouses support a configuration file and command line options in SnowSQL to specify a default warehouse, which is characteristic C. Additionally, the size of a virtual warehouse can be changed at any time, which is characteristic E. These features provide flexibility and ease of use in managing compute resources2.
References = [COF-C02] SnowPro Core Certification Exam Study Guide, Snowflake Documentation