Virtually every website that accepts credit/debit card donations will ask before processing the charge whether the donor would like to raise their donation to cover the processing fee. This is optional for the donor, but at least gives us a chance to recover the fees we pay to accept online donations.
This feature is a deal breaker for us. It was promised to us when we bought into Blackbaud over a year ago and still has not happened. We will definitely be shopping around if they don't implement this by the time our contract is up. I've seen threads of people asking for it for years. This should be one of their TOP priorities. Many donors want to pay the processing fees and even ask how they can help us with that!
We would love this feature for event registration as well!