Hi George
Thanks for the function which did what I needed.
I did a bit more testing of the possible delete bug and what I noticed is if you add your first ticket via the Events Calendar WooCommerce extension it creates two records in wp_postmeta, one of which has a blank meta_value. If I delete the ticket in the Event edit screen, it deletes only the row with a value for meta_value. If I click the link to Edit in WooCommerce and I delete it permanently from there it doesn’t remove any records from wp_postmeta. This therefore can create issues with your default cost display function.
This is the SQL I am using:
SELECT * FROMwp_postmetaWHEREmeta_key= '_EventCost'
Hope that helps.