Keep in mind that this only applies to pokemon that hold items naturally. It wouldn't work for say, on wurmple because they don't have any wild hold items.
just curious,say a pokemon has an item duirng battle,but I don't steal it,at the end of the battle could I get that item from pickup?(probably not i'm guessing)
here is how compound eyes works you have that pokemon in the lead team position and when the pokemon in the wild knowingly holds that item shows up switch it out with a pokemon that knows thief/mytiena and one that knows covet/linoone
both of those moves take the held item if the wild pokemon is holding it
or use this as a helping move for the battle frontier it all ways takes the held item