Scuttlecrabs, shrooms, and tunnels

I'll have to test this, but I could swear I saw a scuttlecrab actually path around a Rek'Sai tunnel entrance in a recent game. I'm assuming this is so it doesn't destroy the tunnel. Meanwhile... shrooms :(

That the crab pops shrooms is an indirect nerf to Teemo because it limits his river control, but I'm not sure what should be done about it. If the crab were to path around them, it would give away their location. If the crab didn't pop them, Teemo couldn't use them to intentionally kill the crab. That's probably not too bad a compromise though.

I'm sure half of you reading are saying "good, his map control is annoying". I agree, but what does he have otherwise? I guess this issue inevitably circles around to balancing shrooms.

For some time, I've felt they should work like Heimer's turrets. That is, they'll arm and explode while Teemo is near, but unarm and only provide vision while Teemo is not near. That type of shroom behavior may finally allow Teemo's kit to be tweaked in other areas.