I wonder if Buffett would invest in a business which didn't increase their prices when they knew demand was going to spike.
Perhaps you will argue that increasing the storage cost for fulfillment by Amazon[1] is an example of price gouging. I will let smarter people answer why it is OK for Amazon.com to charge more during the holiday shopping season. I'd imagine the simple reason is greater volume of transactions. However, with the way Amazon.com does storage, a 33% hike looks strange.
[0] “He’s a great businessman and a good guy, too.” http://blogs.marketwatch.com/thetell/2013/09/20/offering-tip...
[1] Currently $0.48 per cubic foot per month Jan-Oct and $0.64 for Nov-Dec. http://services.amazon.com/fulfillment-by-amazon/pricing.htm