A lot of shows have a problem with vendors trying to take advantage of their shows by hosting events in the hotels the show books (or right next door). For example, instead of paying the tens (or hundreds) of thousands of dollars to book a large booth at the show, someone might host an event at a nearby restaurant.
This is often called "outboarding," and is frowned on by basically the entire trade show industry. Lots of companies have been shut down in very similar situations. Most big convention hotels have policies against outboarding.
Yeah, you might be a "partner" of the exhibiting company, but in this case you're acting more like a competitor - and a somewhat disreputable one, at that.
They probably saved a couple of hundred thousand by hosting this at the restaurant, but now they've pissed off their "partner."
There's a similar practice called "suitcasing," where someone attends a show, doesn't pay for a booth, but runs around selling their products to attendees (spend $2000 for a badge an a hotel room, instead of $30,000 for a booth). Generally, if you get caught you immediately lose your badge, and are usually banned from ever attending that show again...