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.