The user ID is not hardcoded, it could also be user ID 2, 3 or whatever.
The message will appear only if you have configured the plugin before with the user ID stated in the message and checked the option 'Share with all users' from this user.
This message will never appear if you didn't configure the plugin before.
What I wrote before is still valid: if you manipulate the database yourself or delete a user you have configure the plugin with, you will need the change the records of the plugin too (user meta data).