I had 3 creatures in play:
Top - Kor tokens.
Middle - Reflector Mage
Bottom - Runaway Carriage with Vigilance (from Gideon1’s 1st ability)
I used Gideon’s 3rd ability on the Reflector Mage, giving it Defender, so it swapped places with the Runaway Carriage.
However, on my opponent’s turn, he attacked with a stack of Thopter Tokens, and they were blocked by the Runaway Carriage. Surely they should have been blocked by the creature with Defender before the creature with Vigilance?