what is stopping me from putting a bright infrared light on my car angled in a way causing the camera to not be able to detect my plate? overexposed? this should be totally legal afaik since nothing is hiding my plate from any view to a normal human?
Ignoring all of the legal gotchas that aren't very realistically enforceable or relevant:
I do not believe you will be able to force overexposure of lettered areas using IR diodes alone. License plates are designed with intentionally high reflective contrast in the offset areas.
Even if you could put enough energy into that area, these cameras have switchable IR cutoff filters that are used during the daytime (making this approach only viable at night.)
Another idea: a visible-spectrum laser + camera on a tracking gimbal? Absolutely could block (or even destroy!) these types of imaging efforts on a small scale.
I like your idea. I would prefer nondestructive methods of scrambling their ability to read.
There are usually laws against making your plate unreadable to plate readers if the readers are used for tolling. Florida is one example.
The question would ultimately get settled in court, I think, but a DA who was feeling cop-aligned and vicious could try to ding you for interfering with police operations by _not_ allowing your plate to get scanned.
These statutes are typically not written with police enforceability in mind: they criminalize "doing something" rather than "having something installed," and a cop isn't typically going to be around or caring/watching when you move past statically-installed ALPR cameras.
good luck with that in some states, like Florida