If Tianna Crownguard is at a battlefield, do I draw a card when I conquer but cannot score the winning point?

Ruling: Yes, you draw a card. Tianna Crownguard only prevents gaining points; she does not prevent the act of Scoring (Conquering or Holding) or interfere with the card draw replacement effect when you cannot claim the winning point.

Sequence:

• When you are at 7 points and conquer a battlefield but have not Scored every battlefield this turn, Rule 466.1.b.2 replaces the winning point with drawing a card. You draw 1 card.
• If you then conquer the second battlefield in the same turn (having now Scored every battlefield), you would normally gain the winning point. Tianna prevents this point gain, but you do not draw a card because you already met the condition for the winning point—you simply don't get it.

Nuances:

• Tianna does not stop conquer or hold triggers from other cards.
• The card draw from Rule 466.1.b.2 occurs because you haven't met the winning point condition yet, not as compensation for Tianna's prevention effect.