Let me just insert my own argument why I think the opt-in/out transponder is a bad idea:
A skilled player, eventually, will be able to tell the difference between NPC and human player regardless. It will be impossible to thus hide from an experienced player by turning off the transponder, while the experienced can turn it off to hide from the inexperienced.
The telltale signs of a human player range from a flying ship type that is at odds with what the typical NPC in the area flies, more unpredictable combat tactics, or just generally un-NPC-y behaviour like sitting around while watching the scenery or chatting with a friend (generally any form of standstill would be a big huge "here is a player" sign).
A real griefer, therefore, will just fly with transponder off and can still pick their human targets, now with the added bonus that the inexperienced player, which are the most susceptible to griefing behaviour in the first place, are unable to know there is a player around until the moment it may very well all be too late.
Another griefing tactic likely to emerge is two players working together, one with transponder on, the other (or several) with transponder off. The first player can then signal the second when a player with an active transponder comes around, invalidating the very game mechanic that should advertise other players when you decide to advertise yourself.
In the best case, when there is very little griefing anyway, the transponder is a lot of effort wasted on a game mechanic that no one needs. In the worst case, griefing will run rampant anyway, and griefers can and will make use of the transponder mechanic for their increased advantage.
A skilled player, eventually, will be able to tell the difference between NPC and human player regardless. It will be impossible to thus hide from an experienced player by turning off the transponder, while the experienced can turn it off to hide from the inexperienced.
The telltale signs of a human player range from a flying ship type that is at odds with what the typical NPC in the area flies, more unpredictable combat tactics, or just generally un-NPC-y behaviour like sitting around while watching the scenery or chatting with a friend (generally any form of standstill would be a big huge "here is a player" sign).
A real griefer, therefore, will just fly with transponder off and can still pick their human targets, now with the added bonus that the inexperienced player, which are the most susceptible to griefing behaviour in the first place, are unable to know there is a player around until the moment it may very well all be too late.
Another griefing tactic likely to emerge is two players working together, one with transponder on, the other (or several) with transponder off. The first player can then signal the second when a player with an active transponder comes around, invalidating the very game mechanic that should advertise other players when you decide to advertise yourself.
In the best case, when there is very little griefing anyway, the transponder is a lot of effort wasted on a game mechanic that no one needs. In the worst case, griefing will run rampant anyway, and griefers can and will make use of the transponder mechanic for their increased advantage.