"Speed limit enforced" by...

There are two common freeway signs with which I have a slight objection:
1) "Speed limit enforced by radar," and
2) "Speed [limit] enforced by aircraft."

en·force [en-fawrs, -fohrs] Pronunciation Key
–verb (used with object), -forced, -forc·ing.
1.to put or keep in force; compel obedience to: to enforce a rule; Traffic laws will be strictly enforced.
2.to obtain (payment, obedience, etc.) by force or compulsion.

When one considers the above definition, it can be realized that a more accurate sign might say,"Speed detected by radar. Adherence to maximum speed limit rules encouraged
by society, incentives from auto insurance companies, and noticed of penalties delivered by officers of law & enforced by courts."

To directly enforce a maximum speed without access to the gas & brake pedal is impossible, unless the radar is being used for some sort of mind control. As for the aircraft, short of a tractor beam or perhaps weaponry, a maximum speed rule cannot be directly enforced.

Happy to note that in Monterey County, the signs correctly read, "speed detected by radar." I'm proud to know that my soon-to-be home county is so enlightened.