I dont think its considered "fixing" the results when you have to guess what the survey is about. "Fixing" would imply that gPotato or the people hosting the survey altered the survey in a way so that and intended result would have to occur.
As I said, the surveys are outsourced to gPotato. You could probably get more real money if you did the surveys on the actual survey hosting site, like iSay. For example, doing the survey here, for gPots, will net you 150 gPots (equivalent to $1.50 US). If you did the same survey on the survey hosting site, they would pay you $2.00 to do the survey - either through a point type system or by some other means...only a few survey sites actually give out real cash. So, in the end it becomes win/win. gPots gets money from the survey people to host their surveys on their site, and the survey site saves money by offering their surveys with a discounted reward.
Also, doing the surveys is not required. You can buy your gPots like most do.