What if people say they want to volunteer, but don't come?

Original question:

I have been with um for a couple of years. From time to time they send me an email of someone who is supposedly a volunteer. I respond to them and never hear again. I have tried to contact staff on multiple occasions concerning this with no response. If I do not hear from someone within a day I will discontinue this relationship. It has been so frustrating to think someone might want to come and then nothing. Perhaps these are all bogus responses.

Response:

These emails are sent automatically when a potential volunteer clicks the "I Want to Help" button for one of your volunteer opportunities. I'm sorry that you have had bad experiences with people not following through; unfortunately, there's no way that we can control whether volunteers will follow through on what they say they will do. 

We have matched thousands of volunteers with organizations over the past few years though, so I'd say not to give up. Perhaps the perfect match is around the corner.