Your entitled to your opinion to be against unsubmerged kill traps and cable restraints and laws against being able to hunt on the "kings lands", etc. etc. etc. no matter how wrong you are and even though by your own admission it's been around 35 years since you had a dog killed in a trap and you've never had one killed in a cable restraint.
Sorry but considering what you have written about your opinion on here your story sounds a little far fetched.
Back in the 70's, you had permission (you don't want to ask permission now but we're supposed to believe you did back then) but the land owner either didn't bother to tell you or you ignored the fact that he had dug holes, baited them with meat and set conibears and you turned your dogs loose there anyway. I reckon if it's true, that shows really bad judgment for one of you.
To tell you the truth, I find it hard to believe that a landowner who had kill sets like that would give you permission to run your dogs on his property without a least a warning that the traps were there. On the other hand your story is much more believable if in fact you didn't have permission and were just running your dogs.
I remember in the 70's a group of coyote hunters around Foristell that would let their dogs run all of God's creation and just drive up and down the roads to try and cut the coyotes off at points where they would generally cross at. These guys never asked anyone for permission and didn't care if they messed anyone else's hunts up. This is probably why I don't have a good opinion about owners running their hounds without permission.
Carry on.....