Will the garbage collector pick up an Instance that isn't parented to anything after awhile?

NOTE - This is a re-post/duplicate question to this here. Though it didn't get much of a response, (since I posted it @ 2:00 in the morning) so I'm asking this again.

I was wondering this as I wanted a more precise solution to yielding a thread. Consider this:

Instead of doing this

local conditional

spawn(function()
    repeat wait() until conditional
    --do stuff
end)

wait(1)
conditional = true

One could do this:

local conditional = Instance.new("BindableEvent")

spawn(function()
    conditional.Event:Wait()
    --do stuff
end)

wait(1)
conditional:Fire()

Though wan't fully sure if an instance not parented to the DataModel would automaticly despawn and get removed after awhile.