On the call: you've probably seen it a few times yourself. When a shot is a long high hook rather than a dead pull the call over where it actually crossed the hazard line opens a lot of debate. The amateur tournaments I've worked usually only have a handful of officials on the whole course. The PGA Tour is well funded and I am a bit at odds that they don't have either qualified rules officials, apprentices or knowledgeable fore caddies and spotters in awkward places in a tournament of this caliber.
To your question of Tiger and Sergio. When I began learning the game and I had questions about rulings on my ball such as taking relief or determining playable situations, my mentor used to ask first, "What would you tell me if that was my ball?"
I always say, "Drop it anywhere you want to." And often I'll add something like, "Why don't you drop it over here, so you'll have a shot" ... because to my duffer way of thinking, it's ridiculous to take a drop behind a tree.