Given human nature, ethical issues are not a matter of if, but rather when they occur in an organization.

Ben and Jerry's Homemade, Inc. is a well known ice cream brand globally.  As part of its mission, it donates 7.5% pre-tax profit to charity.  It expects its business partners to engage in similar philanthropic activities.  If a supplier has no charitable history, it will refuse to enter into a business relationship with that company.  

Is this a good business practice?  

What concerns/issues would shareholders have regarding this policy?