While in general I tend to agree with the concept that the units were denominated in USD and refunds would have been that amount, in jjiimm_64's case he was explicitly promised his BTC51 back, with no exclusions. If Hashfast was worried about unlimited liability on the BTC51 in the event that Bitcoin went to $1M, the simple solution would be to just not convert that BTC to USD. Yes that opens up the possibility that BTC would go to 0 and their payment is now worthless, but that's the choice they make when they offered him a full BTC51 refund.
EXACTLY. I had 250 coins that were offline, to be saved... when HF convinced me that my coins where safe if I did not get the hardware.
edit: i ended up ordering 4 BJ at about 211btc.