if we allow decoding files wont that mean we support warez O.o
A member asks for a file to be decoded which he bought and has the rights to because he want's to change the layout. He bought it 6 months ago and since then the site where he purchased it has gone offline so no official support is available. He want's to decode it and is perfectly entitled to do so in such a case and request help.
This could be done But how staff is going to check whether the end user has the permissionsIf you go adding a rule don't just ban requesting of decoding a file completely. Their are loads of legit cases. Have it something like "you must have permission to decode the file in question".
You don't have to waste your time checking decoding threads. This is a community you have to remember where members report this stuff. If someone tries and sells a premium template they don't own like a nulled theme that's for sale on themeforrest it's not usually the staff who notice but the members and end up reporting the thread. The seller usually get's banned for trying to sell a nulled theme.Every time I have seen a decoding thread I have closed or deleted it. The chances of someone doing it for legitimate reasons is highly unlikely in my opinion. If you want files decoded then go to hacking or coding forums, simple.
Unless you want to become a Mod (Which I would be happy if you did @Mr Hapz) and help out towards the deciphering of legitimate vs illegitimate decoding threads then I guess not much will be done about it, I sure do have better things on my time to do than differentiate between decoding threads.