We have some players who are careless when sitting North (and/or East!), and fail to put an X against a contract that has been doubled, though the score would be correct for a doubled contract.
I have read that it is normal (horrible cop-out word!) to accept that the score is right, and if appropriate, treat the contract as doubled.
In an effort to get players to be more precise when writing in travellers, I only award a 'doubled' score if there is an X, and have put a note to tjis effect on the club website. Is this permissible - although not an EBU club and in Spain, we strive to follow all WBF and EBU laws.