Reducing the impact analysis within a long running relationship to a single transaction is too narrow. People observe how other people are treated and draw their conclusions even if not impacted. People may tolerate some abuse but it moves them closer to leaving next time. Money lost in the outage may provide for a budget creation to look for an alternative.
A lot of people making those decisions don’t care about a refund because it’s other people’s money anyway. In my experience only small companies care about that.
Focussing on communicating open and honestly allows them to explain the crap they’re going through because of your mistakes to their bosses, so in fact you can help them save their asses, and they’ll save your ass in return. This is much more important and valuable than a refund.
So you should ALWAYS communicate open and honestly, and offer the refund as an option for clients who do not have a boss to account to.
I've seen cases where it was actually _more_ work for a business to process a refund. That money has to go all the way back through accounting/financing, be re-added to budgets for the appropriate groups, etc. It's not something done all the time so it takes extra time for those working on it. It's not like a Visa credit card getting a refund for a wrong coffee order.
