CheatHappens claims that the user contacted Blizzard and was told, "while single-player games only appear to be you and a computer at first, your achievements and gamer score also carries weight and prestige for your online play."
Shacknews asked Blizzard for more information on these bans and received the following statement from a company representative:
Blizzard Entertainment is not banning StarCraft 2 players just for using single-player cheats. There's been some confusion in the last couple of days about the suspensions and bans meted out to players caught cheating in StarCraft 2. It's important to point out first, that many of the 3rd-party hacks and cheats developed for StarCraft 2 contain both single- and multiplayer functionality. In order to protect the integrity of multiplayer competition, we are actively detecting cheat programs used in multiplayer modes whether there are human opponents or not.
That said, players who opt to use any type of 3rd party hacks do so at their own risk -- there are already built-in cheat codes for StarCraft 2 single-player that can be used safely. Blizzard Entertainment has always taken cheating seriously and will continue to aggressively crackdown on players who cheat in our games.
Please keep in mind that CheatHappens, a site that creates and distributes trainers, is not the best source of information for bannings over the use of the very programs it distributes. Also, the user that claims to have played no multiplayer games was only suspended, not banned.
Blizzard's decision to ban or suspend players using trainers is not surprising, considering that the game is always online and many of these programs could potentially be used online. For those that have truly only used these programs in single-player games, I would hope that they only received suspensions.
If you believe you've been wrongfully banned, please let us know so that we can gather more information on the issue. For now, refrain from using third-party hacks, cheats, or trainers if you value your account.