I've never understood this business of the third goalkeeper at a major tournament. I've felt for years that teams should select 2 goalkeepers and a specialist penalty stopper, precisely for this kind of occasion. The only time I can recall that a third goalkeeper has ever been used was in 1978 when the French needed theirs. Although this sounds like a sad piece of tivia, it's the goalkepers name that sticks in the memory - Dropsey! Possibly the worst named goalkeeper of all time.
I remember England nearly needing theirs once (Chris Woods) but they didn't. I also remember England flirting with the idea of nominating Glen Hoddle as their reserve keeper and thus allowing them to utilise an additional outfield player in the squad, as by all accounts Hoddle was a passable keeper if needed in an emergency. I definitely remember that at the last world cup and African nation or comparative minnow did this, and FIFA sanctioned them by insisting they he had to play as a goalkeeper (basically FIFA made the rules up as they went along).
You select your squad of players. There is nothing that says you have to pick X number of defenders, Y number of midfielders etc The balance of the squad is at your discretion. So far as I understood the team concerned were within their rights to do what they did, and the fact that FIFA intervened on their selection suggests so too
I have seen this specialist goalkeeper tactic used occasionally in play off matches, but what usually prevents it happening is that the number of substitutes allowed has been exhausted after 120 minutes. Krul had only saved 2 penalties from 20 for Newcastle prior to last night, which is hardly specialist territory, in fact it's below average (penalties go at about 78% in the Premiership) so he should be saving about 4-5.
I suspect that we'll discover in the next few days that all of this was done on the training ground, as the Dutch spot kicks themselves were very well executed and we'll probably find that Krul stopped more than the other keepers trying out, and that the penalty takers themselves expressed the view that he was hardest to keeper to beat.