Monsters that are used to Xyz Summon are called ‘Xyx Materials’, and are placed underneath the Xyz Monster, to show that they are attached to it. Monsters that have become Xyz Materials are not treated as cards on the field. When an Xyz Monster leaves the field, all of the Xyz Materials attached to it are sent to the Graveyard. If an Xyz Monster is flipped face-down, or becomes controlled by the opponent, the Xyz Materials are not sent to the Graveyard. They remain attached to the Xyz Monster.
Leaves The Field
Some monsters have effects that activate when they ‘leave the field’. For example, these effects activate when the monster is sent to the Graveyard, or is banished, or is returned to the hand or Extra Deck. When a monster on the field is shuffled into the Main Deck, or becomes an Xyz Material, it is no longer a card on the field, however its effects that activate when it ‘leaves the field’ will not activate.”
At last, sweet justice! Official rulings can finally clear out all the mess regarding these cards. Not just that, but now Tour Guide and Sangan became just "meh" due to not being able to search (as it was supposed to be all along). With this, we can at least have Xyz monsters be as balanced as they should have been.
Now if only we could solve the problem with priority...