hmm.
your concerns are mostly based on the METV, while as I see it, the DTV represents a fundamental change of concept.
the METV was for tourists to come and do touristy things, while the "digital nomad" type of DTV is explicitly for working remote.
maybe it could be a good thing to come prepared with printouts of Immigration's webpages about DTV. If that fails, I also have my attorney's business card with me.
P.S. to directly link to a post, you can hover its date, such as "posted X hours ago" or "posted November 9" and right-click to select "copy link"