I use only Linq to SQL to access the database, so I assume that you can disable query validation ...
So, you don’t care that people embed HTML / javascript on your page, which will allow them to do cross-site scripting attacks? Parameterized queries will only protect against SQL injection, and not all attack vectors.
It is not safe. Linq To SQL runs a project against SQL Injections because it passes data as parameters.
If you disable validation, you will discover cross-scripting issues.