The best solution would be to fix your real problem with the online metadata lookup, so that you can actually get metadata through the system. This is discussed here:
http://yabb.jriver.com/interact/index.php?topic=90226.0However, if you really don't want to get metadata for a particular set of files, while preserving automatic Metadata lookup for other files (where it actually works), the simplest solution would be to:
1. Tag those files with some [Media Sub Type] other than TV Show. You can do this automatically at import time if you know other details about them (their Series, for example) with
Tag on Import rules.
2. If you want them to be separated out from your "regular" TV Shows in your Views anyway, then you're done, and can just make a new View that shows only this Media Sub Type. However, if you want them to be all shown together, but have those special shows never get looked up, then you'll need to alter any Views where you want them both to show to include
[Media Sub Type] = TV Show, <Whatever You Picked In Step 1>. That way, they'll still all be shown in the view together.