He must have been using a pre-production or preview copy of the rules. My kickstarter edition rules certainly don't mention a tiebreaker and explicitly say that if neither player has a majority of cards then the line is uncontrolled and doesn't score (if still uncontrolled when the game ends).
the conditions for control are
1. Your digit must be faceup on more cards than the other player (colour irrelevant) AND
2. there must be at least three cards in the program line
if neither of these conditions are met, then neither player is in control of the program line and neither player would be awarded points for that line if the game was to end