It sounds like you're asking why PRAGMA cant be used to affect the table only during its creation. The main reason for this with SQLite is that SQLite stores the table definition as text. If you run `SELECT sql FROM sqlite_master WHERE type='table'` you can see all the statements that are used to create the tables. Therefore, in order to specify which tables should be strict, you would have to have something in that statement that indicates it. The other option would be to have the flag control all tables (even ones created previously) which prevents incremental adoption.
