The example of somenoe with a bobcat tag shooting one in your trap would still be illegal. Yes, they have a tag but you dont. You set the trap and legally, that cat would have to be released if you, the trapper, yourself did not have a bob tag. The odds are good you wouldn't get caught but it would still be ilegal because you would have assisted in the taking of the cat without a permit.

The term fair chase is a subjective thing. In some areas you can pursue deer with dogs. In those areas it's legally fair chase. Likewise, you can bait deer in some states but not in PA. Fair chase is is also defined differently for different species. Thats just the law. You can bait coyotes but not deer. You can trap some animals but others must be hunted.

same with Sunday rules. Crows and yotes can be hunted Sunday, most other species can't.

The bottom line is that there are laws that may not always make sense to everyone but they are still the law. Who knows what the thinking was when it was decided not to allow semi auto riflesfor hunting or trapping. It really doesnt matter. It's the law. The answer is to try and have it changed not to disobey it simply because it doesn't make sense to you