Apple's job is not to do a check against trademarks when reviewing an app. They test for bugs and malicious code. The test private API's aren't being used and they check it meets the public guidelines document.
I've released an app before which infringed on a trademark (accidentally, I didn't realise the name of this sport was trademarked). The owner of the trademark emails Apple, who forwards it to the developer who is told to take action immediately and respond to the trademark owner. If there isn't a quick resolution Apple will take down the app. They even have a check box when you are submitting an update which tells them if you are updating for a legal reason. I presume they would then expedite the review process.
I've released an app before which infringed on a trademark (accidentally, I didn't realise the name of this sport was trademarked). The owner of the trademark emails Apple, who forwards it to the developer who is told to take action immediately and respond to the trademark owner. If there isn't a quick resolution Apple will take down the app. They even have a check box when you are submitting an update which tells them if you are updating for a legal reason. I presume they would then expedite the review process.