>> can camera installers just add an additional infrared filter to their setup?

Yes - your smartphone camera already has one unless it's old and/or cheap.

Also, your LED baseball cap draws much more attention to you than anything else. That screams "look at me, I have something to hide". If you weren't on their radar before being seen in it, you almost certainly are afterwards.

That type of behavior can also trouble you in unrelated matters. EG, evidence of you wearing that to foil security cameras could be circumstantially presented to make you appear deceptive or conniving.

tldr; don't do anything to stand out if privacy is your goal.