Not a collector myself (witness my expansive machine collection of...one ), I have never understood how this preorder craze even began. In most other businesses, putting 50-100% of the price down before a product is even proven/produced is pretty much unheard of. Even if you put your name down for an exotic sports car, you are (AFAIK) never asked for the full sum up front to finance development of the model.
It appears small pinball startups have taken the crowdfunding idea from Kickstarter and applied it to our hobby. Which is hardly ethical in my humble opinion. It should be made totally clear to the prospective customer that they are becoming investors. The risks should be stated clearly (which is a requirement in most other crowdfunding situations, Kickstarter forces clauses on the risks for example).
At least then customers would be able to accurately asses the risk and decide whether they are willing to risk 5-10k for the chance of possibly receiving a machine as ordered.
I will personally never pre-order anything of substantial value. If a company wants me to finance the development of a product, I expect equity stake, and so should *all* financiers of pinball startups.
If not, the endless row of fiascos will only continue.
(Sorry for the negative vibe. I'm just so disappointed in DP mishandling one of my favourite movies and a machine I was looking forward to playing...)