Hi, my son also finished NAPLAN (Year 3) earlier this month.
The results are due out at the end of August.
Some of my son's classmates were stressed out by the tests (not to mention their mums). One kid threw up and two cried.
Nevertheless, I think it is a good thing, having their stage of learning benchmarked in the middle of the primary years, so something can be done to address any weaknesses before it becomes a bit too late. Either the kids did well and get duly recognised, or there is some room for improvement to work on in the next two years. All good.