I don't have the answer, but if your website has the eloqua Tracking JS included, you don't need to enable the tracking on the email specifically. Unless for links going outside of your website.
I think link tracking is always off by default. When creating the asset the user must "track all links" or manually select them.
I have to remember to go check it for each email I send out bc sometimes my designers "forget" or the track was not saved correctly.
I wish it would track all by default though....