Actually on this note:

"However, if I am visiting somewhere and the machines available nearby happen to contain non-free software, through no doing of mine, I don't refuse to touch them. I will use them briefly for tasks such as browsing. This limited usage doesn't give my assent to the software's license, or make me responsible its being present in the computer, or make me the possessor of a copy of it, so I don't see an ethical obligation to refrain from this. Of course, I explain to the local people why they should migrate the machines to free software, but I don't push them hard, because annoying them is not the way to convince them."
- rms

Man, I wish more free software advocates realize this.  In some ways I think some people are unwitting proponents of proprietary software in the free software movement, because their extremist stances about proprietary software actually turn people away from wanting to deal with free software.