Yes, when booked on Delta.com there are lots of warnings like the one below.
However, when booking on a 3rd party site or corporate travel portal there does not seem to be nearly the level of notification. In my corporate travel portal I would need to look at the fare basis to know it was an E fare which buried 3 clicks into the data.
Could these E-fares just be a ploy to first draw in customers via the various booking sites (delta's price showing up as lowest so people click on them), and then by showing all these negatives trying to sway people to select the (slightly) higher price to get all the benefits?