If your procedures show that you are complying with the requirements and your file is documented with the delivery date I believe that is sufficient – a signature isn’t required and, I agree, may be difficult to always obtain. The commentaries to Reg B and Z note that provide or deliver is deemed to be 3 business days after the appraisal/valuation is mailed or when there is evidence of actual receipt (for email consider e-sign). So, if you have documented when the appraisal was sent should be sufficient documentation to show compliance. A formalized and consistent process for documenting delivery would be a sound addition to your procedures.
