A: We here at Looney Labs do not like what are called “memory conditions.” One should be able to look at the table and accurately see the state of things, even if one has left the room for a bit. If we had to remember which of your Keepers had been played before or after you “put the Ring on” and became Invisible, it would be highly annoying, and someone returning from a bathroom break would have no idea which of your Keepers were invisible or not.

So… as long as the Ring is face-out in your hand, all of your Keepers in play are Invisible. It doesn’t matter when they were played relative to the invocation of Ring’s power.

Think of it thematically this way: if you handed a box to Bilbo while he was wearing the One Ring, the box would become invisible, just like the clothes on his back.