well why i liked this article is that i liked the way ikea approached the problem. They would consider both the design and manufacturing process together, thus reducing integration problems if these two stages were seperate in the product development cycle.
A creative approach to the problem (by looking at it upside down instead of right side up) can also easily solve the problem. I do not think when one is purchasing a mug they would consider what a mug should not hold, since it's what they want to put inside the mug that is more important. However, this should be a concern, since stagnant waters may increase baterial activities or pose mosqitoes hazards.