My cynical irony button just lit up here and it's just too tempting to ignore. So rather than build up and grow the fan base, stiff 'em for a few bucks while they're stupid enough to pay?
Yes, it's definitely a sales tactic to offer a 'sale on a limited-time basis', but it's been proven time over time that running a sale for a long time results in more long term revenue.
I don't object to the sale, just to the utter lack of warning/notice and the ridiculously short time for the sale. Over 17 Million players worldwide. Wouldn't you rather try to sell to all of those 17M instead of deliberately reducing your potential market (by offering a sale in the summer and keeping it short)?