The idea of a mentor is to teach you the business, not just be a rubber stamp man. Some states mandate that the mentor go with you on a number of inspections, and be present during the formation of the appraisal.
Many states are adding rules reagarding how far in proximity you can be from your mentor and that your mentor MUST be physically with you for your first 50 or more 'inspections' of the subject property. So, in many states this is absolutely illegal; in all states it is absolutely unethical. IMO, it's just plain stupid.