Sources offer contradicting points of view, so the most important thing is to communicate the issue with your guests.
Recently, I planned a small celebration with friends and family for my husband's 30th birthday. After realizing that it would be impractical for me to cook for and serve twenty guests in my own home, I decided to have the dinner at a local restaurant.
At first, I was a bit nervous about this aspect of party planning. If I was not cooking for this group, would I then be expected to pick up the check for everyone?
Even Emily Post could not give me a clear answer.
Ideally, if money was not an issue for me (alas, it is), then I would have loved to treat my friends and family to a dinner in my husband's honor. However, if I were to do so in a financially responsible manner, I would have had to ask the restaurant to provide a limited (and thus cheaper) dinner menu for my guests, and to keep alcohol purchases separate from the dinner check.
So, that was one option. But after discussing the issue with many of the same friends and family members who would be attending the party, the consensus was reached that everyone, including me, would have a better time paying for themselves. The guests could order whatever they wanted from the restaurant's delicious and extensive menu, as well as purchase any beverages (both alcoholic and non-) they wanted during the dinner service. Most importantly, I wouldn't be burdened with an expensive bill and the guilt of limiting my guests' experience.
But what is the etiquette in this situation? Was it rude that I asked my guests to pay for their own meals? I did some research on this issue and found nothing but contradictions in the way of answers, and mostly in the form of squabbles on message boards. While many sources claimed that as the one organizing the event, I should be responsible for the bill, other sources argued that in modern times, it's totally normal and accepted for guests to pay their own way-- as long as the guest of honor does not pay for himself. That wasn't a problem, because I was obviously treating my husband. Ultimately, the most important insight I gained from this research about who should pay is that it all depends on your guests.
When you are expecting guests to pay their own way, it's crucial that you have reasonable expectations. The restaurant should be someplace that they can afford. Thankfully, I know that my husband's closest friends are all relatively established in their careers and that an evening out would not be a financial burden for them. Although I wouldn't want to celebrate a milestone birthday at a fast food restaurant (unless, say, I was under the age of 10), I wouldn't expect my friends to join me at an exclusive fine-dining place, either. Know what your guests can afford, and stay within that scope.
This ties in to the most important lesson of all in this (and all) tricky situations: communicate clearly. As soon as I made group reservations at the restaurant (a month in advance), I sent out an email invitation to the guests. I tried to avoid referring to myself as hosting the event (which might imply that I would pay), and instead asked my guests to join us (implies self-responsibility) at the restaurant for a celebratory dinner. I also provided a link to the restaurant's online menu so that everyone could see what the prices were and how much they could expect to pay.
Going along with the principle of having reasonable expectations of your guests, as the one organizing the event, it's important that you don't double-dip in your friends' wallets! In my invitation, I purposely included a line about presents not being necessary, because their presence was their gift. This further adds to the message that guests, in lieu of a traditional birthday gift, were expected to pay for their own meals instead as they joined us for a celebratory dinner.
Of course, no birthday celebration is complete without a birthday cake! Although I didn't pay for everyone's dinner, I was glad to provide dessert for everyone, as well as party favors (miniature whiskey bottles featuring photos of my husband with his friends and family) to thank them for attending. Planning early and communicating clearly allows you to be considerate of your guests when you are organizing a birthday dinner at a restaurant. Knowing what they can expect ensures that everyone will have a memorable and happy celebration.