Dinners

So, I like to think we have a policy against going to dinners. Of the fundraising variety, that is.
This policy has two prompts:
1 - they are often boring, and the only way to avoid them without insulting people is to have a blanket policy.
2 - they cost too much. I would rather give $X to an organization that spend $X to go to a dinner where 100+ of it is not tax deductible. When do we ever spend 200+ for diner out together
I've made exceptions in the past when I was invited to dinners for free. I am also in principle open to dinners that don't cost that much (eg our shul, which has lunch on shabbat in the social hall...) They raise money by the infernal adbooks, but at least the overhead there is low...
So...now I was invited to a dinner for half price (Still a lot). The organization is one i am fond of, and their dinner is unusual in that it has Torah-classes beforehand (so one could in theory make an exception without jeopardizing future dinner refusals). They want me to come because I have learned and taught there, so I can help give donors fuzzy positive feelings about the place.
I'd probably rather donate the cost of attending (though I can't say I will actually add to what I normally give them) than attend, but it seems they think otherwise. So, what to do? And is there any hope of escaping dinner attendance as a grown-up?