The map Terenas Stand is one of the World Cyber Games maps and recently a discussion about abusing mercenaries was fired up. Now, WCG has edited the map so it is no longer possible to do so.
Using imbalanced map in tournaments that favour one race is often heard about, and complained on. In this particular case, the organizers have decided not to simply remove the map, but to change the rules for the map. We are talking about Terenas Stand in the World Cyber Games, where discussions on using the mercenary camp to hire units in order to do such an early attack that it is very tough for your opponent. Because of this, World Cyber Games has put up a new rule regarding this map, saying:
Assassin and Murloc can only be purchased at the Mercenary Camp after all creeps have been killed or the area is completely creeped. Violation of this rule may result in a loss by default at the referee's sole discretion.
The discussion fired up especially when
MYM]Moon used this strategy to take down 
4K^ToD in the WEG Masters 2006, killing ToD after only five munites using units from the Mercenary camp without creeping there, by simply luring the creep away with a wisp.This rule will also apply at the popular online tournament inCup, as it works as a German qualifier for WCG. Will other leagues take after this rule? Only time will tell.
* Update: The same rule appeals to the WC3L now as well.
Links
WorldCyberGames.com - Official game section with rules
inWarCraft.de - Source (German)