The rule in question is:
“Winner must keep same starting character, but can switch the order of assists.”
- EVO 2k 2012 ruling
However it seems rather confusing as this implies you cannot hold assists during the load screen, but can switch your mid and anchor characters at whim on the player select screen. This is NOT the case. The actual rule is you MUST retain same character order as of player select screen, and you are allowed to hold assists to change order at the loading screen (this will change your starting character and is allowed).
I discussed this last year with Mr.Wizard
A lot of tournaments copy and paste rulings from EVO and it is very likely this rule has been misunderstood since the issue is rarely challenged as most people do not counter pick at loading screen. If Mr.Wizard and the community could agree to a better wording to clarify this, it would be helpful and would avoid an opponent protesting midmatch and creating an issue of DQ for pause or replay with the opponent aware of the counterpick once resolved.
Proposed wording: “Winner must retain same team and order at player select screen, but may reorder by holding an assist during loading screens”