Baymard Institute has another blogpost about using placeholders (called "inline labels" in the article) on mobiles.

They call it "false simplicity": while it appears using placeholders *instead of labels* cleans the interface up and makes it simpler, in fact it just increases frustration and errors.

http://baymard.com/blog/mobile-forms...-inline-labels

The "Houston" example is very incredibly obviously one where the builders of the form never even once tested on a real human being, because they would have at least corrected their error message (which is what I'd expect most developers to do, rather than introducing real labels). One grandma and her bridge club, opportunity missed.