You would want to use live_snippet_* functions for that, not adding dummy scripts.
The obvious caveat is that the code ran this way is not "sandboxed" - it can do anything that your game code can.
So, for modding purposes,
- TXR allows minimalistic scripting with custom syntax/function sets.
A two-part tutorial is available to explain how everything works and how you can extend it to do what you need it to. - Apollo runs Lua code.
You choose what can be accessed. - For larger commercial projects (e.g. Rivals of Aether, Forager, Nuclear Throne) I license and handle integrations of a larger system with a GML-like scripting language (and some syntax extensions - see NT documentation for overview), sandboxing (to the point of picking which variables of which instances can be read/written to), and scoping (each mod can define its own scripts, globals, and so on - without risk of interfering with other mods).