In one of the many legal interpretations that I have read on this lately.

It says " the Employee must not be required to answer the phone, during the rest period, but that the employee may willingly answer the phone without resetting the rest clock"

In one interpretation they said if you're on reserve for 7 days, and don't fly it's considered rest, but if you were called any of the 7 days it's not rest so I dunno

The " on call thing " is the industry standard for 135 operators, I cannot imagine a whole country of 135 operators violating a reg and getting away with it, I personally have never heard of anyone getting violated for rest time regulations.

I would imagine that most FSDO's turn a blind eye to the practice because the cost of the extra pilots to cover the gap would cripple or kill most small 135 operators and realistically almost any flight could be canceled because of schedule conflicts if someone were to start arguing about duty time and being on call.

As far as snitching people off for your interpretations of the regulations, you might wanna be real careful, for you might find yourself in a civil court defending yourself for defamation.
Just ask the flight attendant's who decided they knew better than the pilots of a US Air flight about deicing the airplane and decided to call the FAA on them.