where do you get the claim $1 produces more than $1 in tax reduction? every company looks to lower their tax liabilities. if they make charitable donations, they can use that as a deduction towards that goal. so they can not do the donations and loose out on a deduction, or they can do it without affecting their profits from sales because customers are giving them extra for the purpose.
It isn't about reducing taxes, it's about getting some sort of altruistic branding/advertising at little to no cost.
It still actually costs the company money in customer throughput, signage, implementation, bookkeeping, etc...