We find out in the Deathly Hallows that a snitch has a "flesh memory" and can recall the first person that touched it. It is claimed that this is to help settle a "disputed capture".
Does this imply that one doesn't need to "catch" the snitch as much as you just need to be the first to touch the snitch? I seem to recall that you need to actually catch it though, which raises the question: Does the flesh memory of the snitch really settle anything?
Scrimgeour says:
"A Snitch is not touched by bare skin before it is released, not even by the maker, who wears gloves. It carries an enchantment by which it can identify the first human to lay hands upon it, in case of a disputed capture."
-- Rufus Scrimgeour, The Will of Albus Dumbledore, Harry Potter and the Deathly Hallows
"Lay hands upon it" is a bit more ambiguous than "touch" because the definition implies to manage with the hands, i.e. to have control of it. So if that reading is correct, then it will settle the disputed capture by indicating which Seeker had first control of it.
I would assume that the enchantment on the Snitch is designed specifically for the purpose, and as a result it uses whatever definition of "capture" that the official Quidditch rules do. It's magic after all.
