You guys all make good points but I guess I just see it as an opportunity to avoid a lost customer, even an unreasonable lost customer that hit a nerve. Hand made pottery sells at a premium and a customer that buys hand made pottery for other people is golden as they are the ones that would seem to constantly come back for more.
Now did the lady really think the pottery should have been in bubble wrap (it really is not an absurd thought) or was she just taking a shot? It seems to be a little beside the point now that she has made it an issue. Now it just goes one way or the other, If she gets a significant discount she likely will remain a future buyer and if not she likely will not be back.
I'd want her back, unreasonable attitude and all. You can always survive without a lousy customer or two, or three, but whatever they don't spend is money you don't get for a few bucks of clay, glaze and a LOT of labor (yours) and this is a small enough market as it is. At the end of the year a few hundred bucks more is one hell of a night out, or an electric bill, or...
Unless I thought I was just being scammed I would cave without even thinking too much about it.