Programs that use treacherous computing will continually download new authorization rules through the Internet, and impose those rules automatically on your work. If Microsoft, or the U.S. government, does not like what you said in a document you wrote, they could post new instructions telling all computers to refuse to let anyone read that document. Each computer would obey when it downloads the new instructions. Your writing would be subject to 1984-style retroactive erasure. You might be unable to read it yourself.
You might think you can find out what nasty things a treacherous computing application does, study how painful they are, and decide whether to accept them. It would be short-sighted and foolish to accept, but the point is that the deal you think you are making won't stand still. Once you come depend on using the program, you are hooked and they know it; then they can change the deal. Some applications will automatically download upgrades that will do something different -- and they won't give you a choice about whether to upgrade.
Today you can avoid being restricted by proprietary software by not using it. If you run GNU/Linux or another free operating system, and if you avoid installing proprietary applications on it, then you are in charge of what your computer does. If a free program has a malicious feature, other developers in the community will take it out, and you can use the corrected version. You can also run free application programs and tools on non-free operating systems; this falls short of fully giving you freedom, but many users do it.
Treacherous computing puts the existence of free operating systems and free applications at risk, because you may not be able to run them at all. Some versions of treacherous computing would require the operating system to be specifically authorized by a particular company. Free operating systems could not be installed. Some versions of treacherous computing would require every program to be specifically authorized by the operating system developer. You could not run free applications on such a system. If you did figure out how, and told someone, that could be a crime.
There are proposals already for U.S. laws that would require all computers to support treacherous computing, and to prohibit connecting old computers to the Internet. The CBDTPA (we call it the Consume But Don't Try Programming Act) is one of them. But even if they don't legally force you to switch to treacherous computing, the pressure to accept it may be enormous. Today people often use Word format for communication, although this causes several sorts of problems (see http://www.gnu.org/philosophy/no-word-attachments.html). If only a treacherous computing machine can read the latest Word documents, many people will switch to it, if they view the situation only in terms of individual action (take it or leave it). To oppose treacherous computing, we must join together and confront the situation as a collective choice.
For further information about treacherous computing, see http://www.cl.cam.ac.uk/users/rja14/tcpa-faq.html.