I'll echo Tony a bit here - I'm a bit of a crowd funding hipster, given that we launched Indy Hall largely from membership prepayments but long before Kickstarter and the like existed ;)
And I've seen lots of our members launch crowdfunding campaigns of different scales for their projects. Some have wildly succeeded, bringing in multiples of their goal. Others have fizzled.
The only consistent difference was that the ones who fizzled did not get the community involved BEFORE the campaign launched.
The network effects of Kickstarter and the like really only kick (ha!) in after some substantial momentum has been shown. Lots of research on successful campaigns shows that early results often dictate ongoing momentum of the contributions.
And most time-windowed sales (event ticket sales, product launches, etc) follow a curve where most of the sales happen at the beginning and end of the window - the middle is sort of like a trough of sorrow where very little action takes place.
But...if a campaign isn't passed 50% before it ventures into that trough, it's VERY hard to hit 100% later when you're trying to pull out of that trough and close the campaign.
All of this is to say: launching a successful crowdfunding campaign is predicated on knowing who your crowd is and how you're going to reach them.
And as for pitfalls - technically nobody is going to be physically "hurt" by a failed campaign but morale can definitely be damaged.
I like to ask these questions: What if you weren't asking for money, but for them to show up to an event? Would you know how to get them to show up? How many would come? Who would show up (specifically)? How many of them would come to a second event?
If you're not sure how to specifically answer these questions for an event, a crowdfunding campaign is likely premature. Instead, like Tony said, focus on getting people together for ANY reason. Show them how valuable and productive and enriching it is to spend time together.
I also did an analysis about how one of the most successful Kickstarter campaigns ever used some of the community building techniques that I practice and teach
to turn it into SO much more than a way to ask for money. I'd say this Kickstarter campaign had more of a sense of community built into it than any I've ever seen. Lots of lessons here worth studying!
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The #1 mistake in community building is doing it by yourself.