It's great that your thinking about this. We are, too.
Your customers' data is always transmitted to the Tickit system over secure connections. Their data only goes two places by default: the databases on our secure servers and our encrypted backups. No third-parties get access.
When you setup your store you can choose whether you want to add Google Analytics, Facebook and other integrations. This means some data would be shared, but it's totally up to you.
We're more than happy to help. Give us a call at 250-900-0355 or contact us below.