Made explicit the rule regarding live video for non-SAR runs

Author: betsruner

content/06_games/00_portal-2.md

@@ -38,3 +38,5 @@ The cooperative campaign is timed as follows:
 Unless otherwise specified, partial campaign runs (e.g. chapter runs) are timed as a
 subset of the relevant campaign, so e.g. Chapter 9 runs begin timing as soon as the
 player loads into Finale 1 and end timing when the player shoots the moon.
+If SAR is not used in a run then the user must submit live video of the run
+as evidence.