Default Sensitivity and CaseInsensitive

A TRUE or FALSE value.
For fields of type DTYPE_ID

Queries are case-sensitive if
Use Default Sensitivity is TRUE and
CaseInsensitive setting in the CFG file is FALSE.

Queries are case-insensitive if
Use Default Sensitivity is TRUE and
CaseInsensitive setting is TRUE.

For Id fields not exposed in the business component (such as the ID field in Opportunity), the User Default Security property cannot be set.