Time to once again discuss the "rounding up/give $5 at the register or charity."
It isn't a tax writeoff for the company. Period. You aren't giving them money that goes to their tax writeoff. That's not how any of this works.
If they say "we donate 10% of our proceeds to charity!" _that's_ their tax writeoff, but you rounding up at the register is _never_ their tax writeoff.
Clear?
Let's go through the FAQ:
* "I don't trust companies" cool neither do I but they have better ways to steal 10 cents from me if that's the plan, ways that don't involve them committing several different kinds of fraud.
* "I don't like the company they are donating to" technically it is the company you are choosing to donate to and you don't have to.
* "What happens to that money?" It goes to the charity. It is also technically _your_ tax writeoff if you want to claim it on _your_ taxes.
There may be more efficient ways. You may not like the company. There are a thousand reasons you might say "no."
But none of them are "you are paying for the company's tax writeoff" (exempting, of course, if they say something like "10% of proceeds" or whatever, but that's not donating at the register).