Their business, their rules.
Yeah the private business (laughable to call major banks that anymore...) can set its own rules but the police could exercise some discretion and choose not to intervene in mask-based trespass calls. I am sure they have other things to do.
Really? A private business can set their own rules?
What if that private business WANTED to allow smoking on their premises?
To my knowledge almost all localities restrict smoking in private businesses.