Chrysler Repair: Key will not turn in the ignition, immobilizer system, key cylinder

Question
My sister borrowed my car and when she went to re-enter it and start it, the key would not turn forward or backward.  She actually has a duplicate key to my car which was made at a hardware store and had used it before.  But today she said that she may have initially put the wrong key in the ignition which is her Chrysler key for her Dodge Intrepid.  Would or could this cause the it to lock up and if so how can you fix the problem.  I did take my original set of keys from Chrysler but the car still would not start.  My dad said that someone told him that if you accidently use the wrong key then this causes it to lock like a security mechanism and therefore would have to wait about 1 hour before the correct key would work.  Please advise.   Thanks

Answer
Hi Robin,
I just found your question in the 'pool', sorry for the delay.
You Dad's theory would be possible if you have a car with the sentry key immobilizer system. That type key has a molded rubber cap which contains a transponder which interacts with a ring shaped antenna on the key lock housing. However, the wrong operating key will not by itself cause the shut down of the engine or the lock to fail to turn. The false key has to be  turned in the ignition switch to the "run" position for that to happen. Your sister couldn't have done that with the wrong key.
I suspect it is a mechanical issue of the pins inside the key cylinder. You might try inserting the correct key into the lock and then tap on the end of the key gently with a hammer to see if that might jar things back into working. Otherwise I am agraid this is a locksmith issue.
Roland