The child abduction risk is actually quite low--there's a whole industry devoted to scaring people about it but the actual number of stranger abductions is quite low. Most abductions are custodial issues and most missing children are simple runaways and not abductions.

However, if you're going to mount security cameras everywhere then you shouldn't omit the bathrooms as you will simply drive the criminals into whatever area doesn't have them.

I think they do serve a good purpose for catching luggage thieves. After all, you have to set down your baggage and look away to do your business.