Aren't there SEC issues with this in the USA? It seems like I heard something about non accredited investors that limits this type of system. But I may be wrong.
I don't know how are the legal aspects, but I think that give the ability to customers to pre-buy the product, or as kickstarter, do a simbolyc investment. Eg. $10 for thank in the honor page and a t-shirt.
I think those legal issues are the reason that Kickstarter doesn't allow you to give shares as a 'thank you' for donating.