Sure, investors are free to request a refund and I doubt Ken will deny this (I don't really know as it hasn't happened yet.) But they also run the risk of having to get back in at the end of the line when evidence of production does actually come out.
With so many pre-order scams, people are beginning to confuse "investors" and "customers."
The guy pre-ordering a miner is called a customer.
The guy buying virtual shares in the Virtual Identity known as Active Mining could be euphemistically called "investor."