This seems to be the attitude of a lot of crafters to facebook events - much to the pain and suffering of fair organisers across the board! So why DO we bang on about facebook events all the time? Hopefully this article will enlighten you....
How facebook works, in the nicest possible way, is like a virus - the more people come in contact with its content, the more that content spreads. Facebook events are NOT just about advertising the event on that day, although of course that is a big part, but they are also about collectively getting together and promoting every single stallholder there in a very quick and cheap way.
Check out the flowchart that shows this spread. You see it doesn't actually matter whether or not the people you invite can attend the event, everyone who doesn't actually press 'decline' will still see promotional material from the event, and given that most of us have options for people to buy online, this is very very useful. If you are one of those people who spends a lot of time on 'like for like' pages, I think if everyone came on board with this it would be much more fruitful in terms of actual sales.
LET'S DO THE MATHS! You can't argue with maths.
Let's take the lower end of the 'average facebook friends' number of 130, and imagine we have an event with 20 stallholders. Let's say each stallholder only invites half their friends - that's already 1300 people. 1300 people who have DEFINITELY had a notification of an invitation - not 'might have seen a share if they were online at the right time'. Let's say that half of those people actually hit the 'decline' button - that's still 650 people left who are going to see some updates from the event in their newsfeed. Let's say only 10% of those people 'join' the event or like a page or picture in it - that's another possible 8450 people (using the lower end of the average) who could be seeing your goods!
I can hear you say to yourself - 'but I don't want to annoy people'. Let's be frank businesses always need to rely to some extent on their friends and if they get pissed off at, at the most, 4 invites per month they aint that great a friend really are they? And if they find a business they love through one of your invites, they're only going to love you the more for it!