affililiates should probably not only read - or at least skim carefully - the terms, but should also screencap a copy for later in case they ever need to show what they actually agreed to when they signed up.
and watch out for programs that state in their terms that changing their terms and conditions is binding and requires no warning or informing of the affiliates - i doubt that is legal since you agreed to one particular agreement when you signed up, but i'm not a lawyer and it's best to avoid this kind of confusion by knowing who will change your terms without warning - or if you know which sponsors do that, you can regularly check their tos.