This kind of increase in odd in partially risky too for the bookies because someone could actually take the risk and end up to win the bet because the team that was expected not to win the match, can luckily score a goal during penalty or could just win in the last minute.
It's not risky for the bookies since after all, a bettor should really have a DAMN BIG LUCK to nail those odds. Even several years of betting won't give a possibility to hit those line of odds. There's even more chance to build a community in the outer space than hitting those huge odds total in a multi-leg parlay bet.
Even the expected payout is huge just imagine the amount already gained by the bookies because of those losses.
If ever someone hit that huge odds the bookies can easily cover it and just a normal day. The next hit might not happened even for months later.