Wouldit be detrimental to hook up one electric brake line to two controllers?

[GM Canada]

I grabbed 3 pictures, I hope these are ok

Gary

[_GonZo_]

Is that what I think, a sound box??? 
Thought before that it was a cargo box.
My god, humanity is crazy 

[Sangesf]

Is that what I think, a sound box??? 
Thought before that it was a cargo box.
My god, humanity is crazy 

Ok....
1.) The box ALWAYS holds a 36v Lifepo4 battery, 12v sla battery, two spare tubes, tool kit, tail/brake light, directionals and electric tire pump..
2.) ORIGINALLY, the box ALSO held 600w amp and 10" sub.
3.) CURRENTLY holds #1.
4.) WHEN I have the money, the back box will hold #1. and #2. BUT, it will be made of diamond plate (treadplate) aluminum and I will probably paint the entire bike fire-engine red and call it, "The Fire Beast", unless someoe can come up with a better name (with "beast" in it).
Unless someone