Security camera warnings are not meant to make anyone feel good. They are designed to scare people. You, yes, you specifically. If they were meant for the "good people", they would say "Good news! For your protection, cameras are recording here 24 hours! We've got your back!" Instead, they always say things like "WARNING: Security cameras recording in this area 24/7. BACK OFF, CRIMINAL." The absolute nicest ones I've seen are still kind of passive-aggressive, saying "Smile! You're on camera!" which is still meant as a threat. I think this says a lot about the mindset of putting cameras up everywhere.
Mokalus of Borg
PS - In some places, I'd rather have them than not.
PPS - But in general public places, they cost more than they're worth.