On or around 9 Jul 2006 02:12:21 -0700, "Teeafit" enlightened us thusly:
I've no problem with 20 mph and rigid enforcement and harsh penalties outside schools - provided it only applies at times when there are people there, like during term time in the morning at arrival time, at lunchtime probably, and at hometime. At all other times, the limit doesn't apply and the camera is turned off.
fixed limits are in any case more or less pointless and only give you a correct safe maximum speed some of the time. At other times the limit may be unnecessarily slow or dangerously fast.