It seems clear from discussion of this ad infinitum that a "convention hotel" is one booked by a convention organizer or event planner in connection with a convention, not simply a hotel which happens to have a location with the name "convention center' included.

That also makes sense. At a massive event, the organizers may well book out 8-10 or more properties, not all Marriotts and then bus attendees to the "convention center".

As others note, rather than trying to find a broad principle, what is your exact concern?