Attacks » Tail Code
May I use Ambipom [G]'s "Tail Code" attack if my opponent only has an Active Pokemon and no Benched Pokemon?
Yes you can, although it won't move or discard the energy. There must be a Pokemon on the bench or you can't move the energy off the defending Pokemon.
Source: PUI Rules Team (2010-01-28)
Attacks » Tail Code
If I use Ambipom [G]'s "Tail Code" attack to move an energy card from the Defending Pokemon to one of my opponent's Pokemon that has an Unown-G attached to it, what happens?
While Unown-G prevents the attachment of the energy to the protected Pokemon, it does not prevent the removal of the energy card from the Defending Pokemon. The energy card is discarded.
Source: PUI Rules Team (2010-01-14)