Product: ImportOmatic List Management
Description: This solution discusses importing list members without matching to existing records or promoting
Please refer to the screenshot below for an illustration of the suggested check box setting to update within your IOM profile. Please remove the check mark from the highlighted check box. Disabling this check box will prevent IOM from prompting the user when a possible existing matching record is found. Deselecting this check box will allow IOM to add all incoming records as list members regardless of an existing matching record. This is assuming that you are importing using the import processing option within List Management, specifically.
You will also want to ensure that you have not made any selection in the profile, to promote list members to full constituents during the importing process. That includes any task workflow applied that includes constituent promotion. Deselect the check boxes in the following area of your profile in the screenshot below: