No, I don't think so. Their website lists reasons why they believe it's not a good idea - and most of the reasons make sense to me:
* It has no real value: an attorney accompanying his or her client to the border for a TN application cannot support the application process until the inspecting officer has issued a refusal or has indicated that there is a problem. CBP will not allow actual attorney representation during the inspection process.
* It creates the impression that the client and the attorney are not confident about the application.
* Port of Entry officers do not like attorney appearances, they want to be able to adjudicate the application without external interference.
* It is too expensive: the additional cost of border representation outweighs the benefit, if any.
* If the application lacks merit, an attorney appearance will not make a difference, the case would be refused whether the attorney was there or not.
* A Port of Entry is an awkward place for an attorney to be representing a client: immigration attorneys belong in immigration court, not at a border crossing.
* It's ultimately just a tool for border attorneys to make more money.
* It's never a necessity: a properly prepared TN application, which is fully supported by legal authority, "speaks for itself."