I placed a bet with a bitcoin book a few months ago on the Blazers to win the Northwest Div. I think it was at 18-1 when i placed the bet. At the time, the amount I bet was worth about $150. Now it's valued at $500 or so.
So this bet got me thinking, how can these books handle the payout on futures bets like this if BTC continues to go through the roof? Let's say 1 year ago someone put 5 btc on England to win the 2018 World Cup at 20-1 odds. If England won the payout would be enormous because of the huge rise in btc since then.