They can, but I would say inserting scripts/styling like this isn’t best practice: it reduces the maintainability of your app, as other developers will have no idea where this styling is coming from.
I dont think there is a setting for this but you could try adding a dataview to the page that is sourced by a nanoflow. That will run on page load.
Another option would be to use the microflow timer widget. There is a nanoflow option now.
But I agree that would be useful. Might be a good post for the idea forum!