There is some built in netsuite behavior that I want don't want to happen but I am not sure how to prevent it. When someone creates a (support) case record, if the customer listed on the case doesn't have an email on file, the email from the case will be added to the customer record. In the system notes it says the context is happening in the UI. Is there anyway to stop this behavior?

Interesting - I just tested this (both on create and edit) and I see what you mean. Definitely not a workflow or anything, it does seem to be built-in that way.

I don't really make the decisions, but my understanding is just because someone wants to be notified of a case's emails, they don't necessarily want to get every confirmation for that customer.

well at least on our end, people can email us and it's captured into a case, even if that person is not set up yet as a Contact in our system

Interesting, even though it says in the system notes that email is being set in the UI context, it doesn't trigger any user event scripts.