Plugin's functionality isn't great under the following scenario:
Doing a buy on multiple sites in a Display Ad Network
I only need to overwrite the medium and campaign for this
I don't want to have to explicitly tag the source for every single link in the ad network, I want the plugin to pick this up
Recommended solution is to modify the current functionality that effectively says, "unless medium and source are found as query string params, I clear out anything that came through as tagged".
Recommended enhancement is to change this behaviour to say if medium is present but source isn't (or vice versa) then medium and source need to be determined, but we don't need to apply this to all parameters...