I'm not sure of your understanding of the word context. Scattered field finds are no longer in "context" they may be in a higher probability area but have all been separated from their original resting place. to truly be in context.. an artifact needs to be still locked in its "matrix" ( the undisturbed soil that was ground level at the time the artifact wound up where is it was) in direct Association with the objects around it like a time capsule. Field finds are all out of context. They may be very numerous in some areas however they are all considered isolated finds by definition. since they are no longer in thier original resting place and no chronological story can any longer be put together by their placement. Here is an example..... If I found an archaic point next to a soda bottle that doesn't mean they were drinking Pepsi a few thousand years ago.