Several cameras (bis)

I am working with Collada now, and there is something I do not understand about collada scene graph.
In the samples (cube.dae or collada.dae), inside the <scene> node, there are the 2 following nodes:

<node id=“Camera” name=“Camera”> … </node>
<node id=“testCamera” name=“testCamera”>…</node>

These nodes are at the same level in the scene graph. I do not understand how and why this is possible.
It may be useful in case of animation, to switch from one camera to another, but no hints/param to enable/disable them.

Is such freedom is in the spirit of Collada? I mean to have an “almost” complete freedom in the scene description, even if it may be sometimes missleading (for instance in the case of several cameras at the same level)? Or when Collada 1.4 will be released, there will be also some documents about restriction/spec to prevent such things?

Thanks for the response

Sorry. The question above is quite immature. I found out in some spec for other kinds of scene graph that several cameras can be defined at the same level. So no problem.
Please do not waste time answering it.