It looks like the bots must be built using BWAPI, an open source API layer for Starcraft that uses ChaosLauncher, an unofficial Starcraft hack. Seeing as how Blizzard is a super litigious bunch of assholes (read up on bnetd , WOW Glider , and Scapegaming  for a sample) won't they just file a baseless lawsuit against the people responsible for this competition? Given their past behavior, I can't imagine that they would be able to restrain themselves.
Honestly, Blizzard makes great games, but they have always fought against free speech, intellectual, and technical freedoms. I hope that Starcraft II falls flat on its face for forcing Internet registration to play the single player game  and disabling LAN play  in the hopes of increasing profit. The sooner that company fails, the better.
 This has not yet been announced, but it's naive to think that it won't be the case