additional option "hidden" and "only read" for affiliate profile field

For group affiliates i think is a good and simple suggestion add 2 option in: merchants _> configuration -> affiliate signup -> filed

This 2 option are used from merchant for choose to:
1. HIDDEN some custom field in affiliates profile (like note textarea)
2. show field but on "ONLY READ" mode, so affiliates can't change value in profile.
(naturally in affiliate signup form field with "hidden" or "only read" option are not show)

I think In this way merchants can easily set some groups to each affiliate, for example "vip" or "upgraded" affiliates,
Then use search filter for this field, and change view of affiliate manager page.