I know you can't be bothered, Flip, but it's always best to check your tickets yourself. 69 is not a huge number to go through. Just think of the people that have 200-400 tickets or even more, and they do it without blinking. At your regular daytime job, do you regularly trust someone else to make your money for you? Probably not. You make your money yourself. The same principle should follow in lottery. Think of it this way: you giving your tickets to the store clerk without knowing what's on them is the same as mailing all your tickets to the Ontario Lottery Corporation and waiting for them to honestly send back your winnings. If you ever do that, make sure to keep photocopies of all tickets and send them registered mail.
To come to the store clerks' of the world defence, I personally have never had a dishonest one, where it comes to lotteries. In fact, they have made a mistake in My favor before, by undercharging me for tickets.