I think the amount they give out in prize
money depends to some extent on revenue intake ( figures for which are not easily available).
But personally I have never known anyone to receive a split prize for Ontario keno, so likely
instead of splitting prizes they just run a program through the numbers to iron out some of the randomness. Indeed some Ont Keno draws don't fit the normal definition
of randomness (it's not unusual to get draws where 14/20 numbers are even or vice versa - 14/20 odd).
Btw comparing Ontario Keno numbers & Quebec banco
http://diffusion.loto-quebec.com/sw3/res/asp/hr_6_AN.asp
Banco numbers are more friendly but from what I understand banco
is extremely popular in Quebec and likely more profitable than Ont keno.