You can use this service to have a non-intrusive micropayment system: imagine Wikipedia, add a simple donation page with a "surveywall" button, when a user presses it it goes to this survey system, once done there is no actual premium content only a "thanks!" page. Thus, no money required and you are donating to Wikipedia, although all of its content is still free.

If these projects just add a special "surveywalled" donation page, this can actually be a good thing for wikipedia and open-source projects. If someone wants to help and doesn't want to spend money you just have to link them an otherwise useless locked page. Now shareware and freeware stuff could also have it. Anyone who wants to donate, just go there. Everyone can still enjoy the content for free.

Well all those nature shows (BBC wild life, etc) try not to disturb what they are filming/observing... although they rarely can be completely hidden.

Or maybe they are just _too_ intelligent to let themselves be detected by us...