Hi Ilkka,
Thanks so much for reaching out again!
When you delete a ticket, sometimes there is some leftover information in the database, called orphaned postmeta.
Via the database, you’ll also want to delete all options with an option name starting with “tribe”, if you wanted to delete all traces of your events and tickets, including organizers and venues.
There is nothing recorded that marks the ticket as “deleted” however.
I hope this helps to answer your question, let me know if anything else comes up on this topic!
Thanks,
Jaime