Hi Georg:
The whole Hendon Mob series "You are the Tournament Director" (link here:
http://www.thehendonmob.com/tournament_director/articles/introduction.html ) is excellent. In fact they are up to 3 in the series now, see index here:
http://www.thehendonmob.com/articles.htmlYou can see by reading the various scenarios that while there is a great deal of increasing uniformity in rulings, there still are a fair number of disagreements, and a number of situations just can't be 100% standardized and depend on the best judgement of the TD at the time, like a judge in any other court.
That particular article you mention is nearly 5 years old and we definitely have more consensus now about card exposure in a tournament than we had then. As you can see, then the field was split 2 to allow a call with a penalty to follow, 2 a call with no penalty, and 2 ruled the exposed hand dead...
But note also that this was on the river and the nuts were already revealed, a raise wouldn't serve any purpose here, it's obviously not going to be called unless the other player also has A-K. I think you'd get different answers if the example had happened earlier in the hand when there were still board cards to come and/or if he wasn't showing an unbeatable hand...
Which brings us back to what we can now say with 100% certainty based on the current state of the rules: exposed cards aren't dead in a tournament, and a penalty may be assessed.