If this is anything like the US Pick 6 Jackpots, then it is Parimutuel, not based on bookie odds.

Essentially, everyone who plays the Pick 6 has their money go into a single pool. The house takes it cut, and the the rest is paid out to those that had a winning ticket. Most of the time, multiple people have winning tickets, so they split the pot. In some cases, in addition to the cut the house takes, they also reserve a specific amount for a "jackpot" which is reserved only for situations where 1 unique ticket wins.

For instance, if there is $500,000 in bets, 20% goes to the house, and then 20% of the remaining amount goes to the jackpot rollover. So $100,000 to the house, $80,000 to the jackpot pool, and the remaining $320,000 is split between the winning tickets.

So really, bookies have no risk with this type of bet.