Final answer:
Anonymous blocks in programming contexts, such as Salesforce Apex, run in system mode, granting full access to all objects and fields but respecting sharing rules and organization-wide defaults.
Step-by-step explanation:
The question pertains to whether anonymous blocks run in system mode. In most programming contexts, particularly concerning Salesforce Apex, anonymous blocks do indeed execute in system mode. This means that when the code is run, it has access to all objects and fields in the Salesforce organization, bypassing user permissions and field-level security.
However, system mode does not mean they ignore organization-wide defaults or sharing rules; those are still respected. This mode is particularly useful during the development phase when developers need to test their code with full privileges to ensure it performs as expected.
The caveat is that when Apex is written and executed in system mode, developers must manually enforce CRUD (Create, Read, Update, and Delete) and FLS (Field-Level Security) to comply with best practices for security.