I just had a run in with the security at Melbourne Airport over my green laser pointer. But they were very civilized especially when I told them I had given an invited lecture and that I take it with me all over the world for such purposes.
When I give plenary talks they are often in very large auditoriums or hotel ballrooms and the ordinary laser pointers don't work so well I need something really bright. They brought in the police who questioned me and then asked me if they could either take it or its batteries. I gladly handed over 4 AAA batteries (2 from the pointer and two spare) and got to keep the laser pointer. I was en route back to LAX at the time so they seemed OK with me taking it out of the country straight away provided it was inoperable on the flight. They told me next time I come in I should put it in my checked luggage. I've not had any problems with it in the US no one ever even asks about it I usually have it in my briefcase along with the rest of my work. The Melbourne security people and the Melbourne police were very nice about it especially when they found out I was an American who had been invited to Australia to give a lecture and was now en route back to Los Angeles. I was also very civilized to them telling them I did not know it was a problem, it was not listed as an item I had to report upon entering the country on the customs form, and that I had traveled the world with it giving lectures. I also told them I knew I had to abide by their laws and I was simply ignorant of any issue with this particular item. They also told me that the law is not a federal law in Australia but rather a regional one and it depends which state you are in - some allow them and some do not. They said this was why it was not discussed on the customs form because that is in regards to federal regulations not state ones. That said, the laser pointer had gone through several scanners for domestic flights in Australia (between Melbourne and Adelaide) before it was "discovered" by the security people at the international terminal Melbourne upon departure from the country.
Overall I found the Australian security to be quite efficient and very polite to me - ditto for the police.