Stealth Questions (and possible change - not a rage post)

So, the most relevant definition of stealth by dictionary.com is:

(initial capital letter) Military. a U.S. Air Force project involving a range of technologies, with the purpose of developing aircraft that are difficult to detect by sight, sound, radar, and infrared energy.

Basically, the term stealth is a list of technologies oriented around making a dude unnoticable to everyone. Including allies, right?

My confusion is around the fact that if your team's rengo goes stealthed, the enemy team just gets those exclamation marks, while your team can still see him fine. That seems a little confusing, since he is technically invisible rn. Shouldn't he be invisible to everyone? Its like with aircraft - a stealth craft is invisible to everyone, both the enemy planes and the ally planes; the dude (lets call him joe) in the next plane can't see the stealthed plane next to him, but he knows its there cause mission control knows exactly where everyone is at all times.

In lol terms, the toplane Jax (aka Joe) shouldn't be able to see his buddy rengo (aka stealth plane) coming in for a gank, but he should know he is there, cause the map (aka mission control) tells jax/joe roughly where rengo/stealth plane is.

Does this make sense to anyone?

Also, this concept could be applied to bushes: unless you have a ward there, your supp walking into the bushes is just like the enemy jinx walking in - it doesn't do anything for you, but gives vision to the dude walking into the bushes. This could lead to some really weird interactions, and follow the bush=stealth theory I think Riot has been pushing.