it gets realy sticky and it depends on what the cause is and where it is held/where the recipient(s) live. one thing that can cause huge problems is how it's promoted-there are postal laws that regulate what can be sent through the mail for fundraising purposes (and you can get fined big time for violating). some fundraisers that include raffles are highly regulated regarding mailings.
some places require a permit, some require that a bank account or escrow account with financial oversite and accountability is in place (to prevent misuse of funds). some require a trust/trustee arrangement.
there are some that can result in being detrimental to the cause (depending on how it's structured, a fund raiser for an ill child can be viewed as monies that have to be used to cover medical costs BEFORE charitable (like shriners) or gov. assissted will pay a portion. so the parents may end up with higher out of pocket expenses by virtue of the having received the funds.
anyone considering one needs to check out the applicable laws and procedural guidelines in their area (as well as consulting with a tax person-without tax exempt/charitable status there could be issues with taxable monies)