These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami. They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: 
If you activate "Ready for Intercepting" after your opponent’s attack declaration to flip face-down the monster which is being attacked, a replay does not occur. Complete the attack as normal. (This must happen during the Battle Step, not the Damage Step.)
If you activate "Ready for Intercepting" and target the attacking monster, it is flipped into face-down Defense Position and the attack ends. (This must happen during the Battle Step, not the Damage Step.)
While the effect of "Light of Intervention" is active, you cannot activate "Ready for Intercepting".
If you chain "Ready for Intercepting" to "Hammer Shot" to flip a monster face-down, that monster will not be included in determining which monster is destroyed by the effect of "Hammer Shot".
Mentions in Other Rulings
Drillago: If "Drillago" attacks directly, and your opponent activates "Ready for Intercepting" from his hand, because his/her "Makyura the Destructor" was sent to the Graveyard earlier this turn, to flip one of his face-up monsters face-down, there is no longer a condition allowing "Drillago" to attack directly, and a replay occurs.