The TOS is a contract between Microsoft and the person who is using the key. Violating the TOS of something, alone is not a crime. Although what the OP is doing may be against federal anti-piracy laws (I am really not sure on this)

Example of how your tips are used.

 
F.B.I. and Chinese Seize $500 Million of Counterfeit Software

A multi-year investigation by Chinese police investigators and the U.S. Federal Bureau of Investigation led to the dismantling of a piracy ring responsible for pirating and distributing up to $2 billion of software. The two-year investigation led to the demise of two criminal organizations - located in Shanghai and Shenzhen - and included up to 25 arrests according to officials from both nations. Microsoft, in gathering evidence it later handed over to the F.B.I. and to Chinese authorities, said more than 1,000 people had notified the company and sent in counterfeit discs. The consumers who sent in the pirated discs were apparently unaware they had purchased illegal software until a notification popped up on their screens. The F.B.I. said that a joint effort with the Chinese authorities had led to the seizing of more than $500 million worth of counterfeit Microsoft and Symantec software that was being made in China and distributed worldwide.

The arrests, according to industry executives, represented the most significant crackdown on software piracy. In the last couple of weeks, the operation led to the seizing by the Chinese government of 290,000 counterfeit discs and certificates of authenticity. The F.B.I. said that Chinese officials had seized more than 47,000 counterfeit Microsoft discs.