You do not need to agree on a 2/3 objective rule - it is a rule. The rules state the following:
Assault vs Assault:
Includes all maps where both teams attempt to take objective(s). Round wins are achieved by either team if they take and hold all objectives(*) or eliminate all members of the opposing team resulting in a server generated round end prior to the time running out in the round. The round is considered a tie if neither team is succesful in completing either of the 2 scenarios above prior to completion of the round time.
*Mout and SF Sandstorm 2/3 objectives will be accepted. Teams MUST record demos for these 2 maps. In order to dispute a match on these maps for scoring purposes, a demo must be provided. Failure to provide demo will result in the dispute being thrown out.
To confirm this, please send all demos and screenshots to fragnader@teamwarfare.com - you have 24 hours. If you fail to do this, the dispute will be thrown out.