... and rightly so.
Unless there's an actual 'ready to ship' product, you run the risk of losing your money. Crowd Funding is an investment, and like investors, you are taking on risk with many crowd funded projects. The reward is usually to be amongst the first to have it and at a considerably reduced price from retail.
Just do a Google Search for "crowd funding failures". Some have raised a lot of coin, had prototypes, and nothing was ever produced. :(
The only Kickstarter project that I've been 100% satisfied and happy with (and that actually made it to market) is the Atlas Throttle Lock. I love it!
All that said, I've been patiently watching and monitoring this product in development: http://www.ridenuviz.com/