Wikis are great sources of background knowledge from all sorts of sources in the world. However, with the speed and fluidity of access to today's knowledge it's all about instant gratification. Kids (and adults too, lets be honest) struggle to differentiate between when using a wiki source is acceptable and when it is not. This is not only because research habits is not taught to younger students, but because as we see every day, wikis are a path of least resistance. When we need to look something up, Google your answer and it comes up right away. Why should the academic research process be any different, or to be entirely honest, more difficult? Telling a student "Because we need to see where your information is coming from, is it credible" is like telling a math student to not only show his work, but also say when they learned it, on a problem that is easily solved in a calculator.
There is no thought process about the types of people who put information up on the internet or if they are a Harvard professor or a 10 year old who is playing on the computer.
This situation cannot be ignored but there is also little that can be done. The line between when and when not to use a wiki is so grey and the gap in the workload is so great, students will find a way to access easy sources of information for their use.