I'm trying to understand UTM parameters in relation to Analytics and Tag Manager governance. I understand what the various parameters (utm_source, utm_medium & utm_campaign) are for, and that you append these as querystring parameters to a link that you want to promote in order to track where a visitor from your site came from. However, I'm unsure as to how this is governed. For example, if someone was running a campaign with a link like this:
http://www.example.com/?utm_source=twitter&utm_medium=profile&utm_campaign=email
...do those source, medium and campaign values need to be set up in Analytics or Tag Manager in order to ensure that they're legitimate? What would stop someone spamming my data by using their own values?:
http://www.example.com/?utm_source=nonsense&utm_medium=haha&utm_campaign=bogus
Many thanks.