The question of animating visibilty e.g. to make a piece of clothing disappear at a certain frame seems to come up a lot. A number of workaraounds have been suggested but these did not suit me.
I actually wrote a plugin to add (via an item on the Edit menu) an animated property AnimateVisibility to a selected node and to trigger at each frame change: it sets the (non-animated) value of Visible based on the (animated) value of AnimateVisibility for the now-current frame. It works fine and I was thinking about releasing it somehow but lamenting a shortcoming (I have to move to the next or prior frame and back to see the effect whenever I change the value) and suspected there might be an easier way. I found that a very simple script can make a node's Visible property animate... but the change does not persist to the saved file (probably this was a re-learning of something I found years ago...). Anyway, I finally went ahead and connected the value changed signal so the effect is immediate.
I use it mostly to make items disappear (as in the simple example images) at the given frame so that render a sequence of frames works as intended, unattended and without a break for manual intervention. I suppose it could also be used to make things blink, to change colors by hiding one instance of a prop and revealing one with the new color, ....
If there is enough interest I could make this plugin available probably by publishing it on Github with an "install" amounting to downloading the dll (I'm only building it for Windows 64-bit) and copying it to your plugins directory.
I'll look for interest posted as replies here...