TSnow,
You are correct on your interpretation of why the rules are there and what they mean. Not everybody in the TA is there to shot or be shot at. There are a lot of other things to learn and practice and the TA is there to offer a place not only to practice, but also to ask questions of the many people (not just trainers) who give up some of their time to help out in there. Having bullet strikes while concentrating on something else detracts from the learning environment.
To engage another player requires permission, not just a statement of intent (i.e. the Check Six). The common method for getting permission is for one player to send a check six and for the other player to send one back as an acknowledgement and permission. Until permission is recieved, either as a return Check Six or as some other form of permission, engaging is in violation of the rules.
If you are engaged by someone without permission, point out (politely... did you understand what the rules meant the first time you flew?) how it's supposed to work and ask them to stop. If that doesn't work, look for a trainer. Problems don't continue for long if a trainer gets involved. Of course, trainers don't have 24 hour coverage in the TA, so you can film and send it in or just mention to one of us when you do see us who the problem was. We will keep a close eye on perceived trouble-makers and help them to learn the right way.
Regards,
Hammer