Do not assume a partial itinerary resolves an incomplete work-authorization analysis.
Use the actual permitted proposal
The applicant needs appropriate authorization for the work performed. Have unresolved material duties and employer relationships reviewed before starting activity based on an incomplete description. Hypothetical example: a fisheries statistician’s customer schedule changes after the employer has prepared a support letter.
Freeze one current version of the assignment before asking for classification. The decisive records are the signed support letter and any customer documentation that shows the duties actually expected on the first day. Compare them with the travel calendar, then choose whether to postpone the start, narrow the initial duties or obtain a revised package.
A recurring error is beginning a convenient portion of the job while material employer or duty details remain unresolved. A later clarification cannot retroactively make earlier activity authorized. If the project changes after review, assess whether the new facts still fit the selected TN basis before work begins.
Keep a dated copy of the final explanation and do not let a customer’s convenience determine the authorization analysis.