I do not know if the bonus material gets remotely deleted from your system
Totem does not now, nor has it in the Past, Remotely deleted files from a members system.
However,
If you Happen to try to update a card that has been removed from the Store
The files will be lost, because the update process overwrites files in the data and models folders with blank files that don't exists.
Files in the Data folder, and Files in the Models folder are subject to being Overwritten.
Card image files.
you can make a duplicate of the original file and name it aXXXX_custom.jpg
this file will never be Overwritten, and will be used 1st, if it's found in the data folder.
( but, Stickers will NOT be Applied to a custom card image )
If you own, and have already downloaded any of the Cards that Have been removed from the store.
Please make a Backup of ALL of the Files in that Cards Data folder and Models Folder.
This is your only way to recover from an Accidental card update.
If you have the Animation files ( .demo and .vghd ) from the Models folder
the Card will still play even if you Don't have the Card image.
A Blank Images does not mean the card is Gone.