If I remember correctly forkeeps, I read a US SC case once that dealt with such fundraising issues, live though, not by mail.
The SC upheld it as a 1st AM right!
As long as the money is used for the announced purposes, there is not fraud, etc.
My research if I was recall was based on a case where a person put on his web site that he would eat his rabbit if X $$ were not collected by a certain date.
I did some research on fundraising, and I remember the 1st AM issue.