I also think that you have to get people to spell out what they actually mean. "I lead with my arms" can be an imprecise way of saying:
"I use my arms to keep my partner in a fixed position while I lead." Torsos are together; leader's right arm is at best firm, at worst a clamp; and leader's left arm is at best fixed, at worst rigid. This creates the famous "frame" used in other dances, and used by some tango dancers as well. The entire body leads, but the arms bring the follower along for the ride. I dislike this because I prefer torso-on-torso rolling, but lots of older "milonguero" dancers use it, and the follower usually ends up replacing pivots with crossing steps.
"My partner and I have a secret signal to make our arms on the open side noodly, so we can do big, flashy arm movements, especially in finales." So, not a lead at all . . . just a signal to say we'll pull our arms up real high, or down to hip level, or back behind me, or whatever while we pose like peacocks. I've done it in choreos, but it looks goofy at the milonga – like, "Look at us! Aren't we just precious?"
Likewise, "I never lead with my arms" is as I said: "I never pivot my partner with arm movement unrelated to torso movement." Of course the arms are still leading, just not on their own!
I'd be interested (seriously) to know whether any double-arm amputees dance tango successfully.