It's all in the thread count not being sufficient for the towels to hold the heat. Another enhancement demonstrating why any sane person ought to book ME3 even if more expensive and less convenient.

Once it has happened though, this is clearly a matter for EC 261/2004 compensation. Given the ECJ's record of expertise regarding commercial aviation, a good chance that it will hold that the lack of an appropriately hot towel is the equivalent of a cancellation, entitling the passenger to compensation.