I'm not an expert at all, lol, but we are trying to save money wherever we can as well. So I think we will probably just put something in the OOT bags to let people know where we'll be and what time and if they'd like to meet up with us they can. We are staying at an AI so, if we just go to one of the restaurants there, they're not going to have to pay for their own food or anything. We will be having a small group around 20.
I think if you don't have it in your budget, its not necessary, but it is a nice thing to do if you can afford it. We were thinking of doing some type of group excursion or something and we will probably pay for that, but we can't do both.
hope this helps!