You know this has been coming to my mind here and there, but shouldn't a brother be able to look up when the lodge meets and just show up to a stated meeting. Of course it's beneficial to know in advance so you don't show up under dressed or over dressed but that is the whole point of the examination of a visitor...
The whole idea around GL to GL communications is around regularity. Trust me, you can have an irregular Freemason turn up and know the same "secrets" you do, and if she's not wearing a dress, you might not pick up that they are from an irregular GL... but you are right.. each lodge needs to guard its own door, but the other side of this thought, is we had a visitor from Chile - and based on his paperwork and story ("I was made a Freemason in the AASR where i did my firs three degrees and I am a MM) I would have declined him - his secrets were also different and his words were as well..... but my GL had telephoned me and vouched for him... Turning up on a lodge is a risk, you might not get entry - and you might be visiting an irregular lodge.. the most assured way to visit is by GL communication.. but if I was going to an English speaking country like Ireland, England, Wales, I would not bother, but you would always have to be very careful you were not visiting an irregular lodge. But I am a PM of 15 years experience, for you as a Freemason of <1 year, be very cautious when visiting... you might break your Ob by sitting in an irregular lodge.