I think this may be a miscommunication here. Obviously, the boyfriend and other guests knew it was to promote the new business venture. (She states that's why they were invited). He may not have passed that bit onto her, though, and just said "it's a party". In her mind, that's food and drinks and a chat. He may have felt embarrassed because she obviously didn't want "in", but the other guests couldn't understand that, because they were all there to "get in". I was once invited to a friend's Tupperware party many years ago, under the proviso, "please come, my other friend is just starting out, and needs the practice to run a party. Absolutely no obligation to purchase". So I went along. If that disclaimer wasn't there, I probably would have refused as I already had Tupperware and didn't need anymore. (That stuff is expensive!)

Also, another time, whilst on holiday in Fiji, we were invited to "spend $20 and go on an island tour, small cruise and lunch included". The catch was, we had to spend 90 minutes listening to their spiel. We knew it was Timeshare, but they kept denying it. So, we sat through it, and toured their "Timeshare" properties, which were gorgeous, but we just didn't have the money to sign up for million dollar beachside views. So, we stuck to our guns and refused to sign, and they had to honour their agreement and give us the tour and lunch, because we'd paid the $20. Being upfront was the key.