Quoted from YKpinballer:
50 is a lot more than 17 and will devalue it. However, at this point in the pre-order mania, people just need to consider it this way: unless you ask for a refund, obviously the pin is still worth what you're paying for it.
Whatever the production run, if you still buy the machine you are deciding that yes... that is the market value. So no change there. The only thing that takes a hit from an increased production run is John's reputation and his ability to get investors in future "limited" production runs. If he's not worried about that, then it's just something you have to live with as a buyer. In the end, you are still paying the going rate for the product and that's your choice. If the increased production run devalued the pin below 17k, you would obviously ask for a refund, right?