How can we know the game isn't rigged?
The old trick of the papers with numbers isn't a fair way to select the winners because we can't verify every single ticket in the basket. I would say it's complex to trust on a site like this. But good luck with the project.
I'm sure that there would be absolutely no reason for Jumbo Ticket to cheat their users, but a high standard of trust is necessary from the user to the service, with the service being a centralized entity. From my post before, I believe a good feature to have for online Bitcoin lotteries would be to get the results from the Block Hash of the Block Header of a predetermined block. It would remove all questions of manipulation.