Just read this on the website of a company who sell OBD port immobilisation. Maybe a little bias as theyre trying to sell something BUT it does all make sense.
Moving the OBD port seems like a good idea at first due to the amount of car thieves knowing the location for each vehicle. and car forums suggest this as the cheapest method to stop your car getting stolen. Sadly this is not the case the OBD port normally has a very restricted harness length ( around 4-5 inches ) meaning if you do remove the port and plug in an extension lead to relocate it the thieves will still know the original port won't be far from the original location point.
This method is common on the Ford ST owners forum, sadly this has caused more problems than it has solved, when taking the vehicle into Ford's for diagnostics or a software upgrade they will refuse to work on the vehicle, if the OBD port is not in it's original location fully working. This is understandable due to some people modifying the looms so the live and negative are round the wrong way in hope it will damage a key cloning OBD machine.