I never let them put a tie through the barrel since it almost always will interfere with the extractor when you close the action and possibly damage it. I loop the tie around the rear of the frame and in front of the toggle knobs and pull the tie tight, that makes it impossible to operate the action. That serves two purposes, it satisfies the need to render the gun safe and it keeps lookieloos from racking the action. I have never had a gun show inspector object to this method of securing a Luger. As far as there being a live round in the chamber, the extractor tells you at a glance if it is unloaded (that includes a 1900 and 1902).
I have no idea why the extractor is still loose after you swapped it out with the 1900, unless both extractors are suffering from a loss of temper (not unlikely since I am almost that old and I occasionally lose my temper
). The same goes for the ejector. The other option is too horrible to think about, and that is if someone hogged out the center tab hole for the ejector in the receiver.