Recommendation - alternative email field

Hi everyone,

My recommender noticed the below field in the LOR form:
"
(Optional) Alternative email (If you are using your personal email account for this recommendation, please enter your work email address which may be used as a verification of your identity if the applicant is admitted.)
___________________
"

Now he's insisting that I send him LOR form request on his Gmail, and he will include his official work email in this field (to verify identity).

Is this practice fine? Or will this be frowned upon by the schools? My first guess is that it should be fine, because if recommender was submitting form from his official work email, then this field is redundant/not required. Schools must have added this field to give more flexibility to recommenders. Can someone confirm please?

Also, I didn't find any existing discussions related to this "Alternative email" field, so I'm wondering if this is something that has been introduced recently?

Thanks in advance!