It makes no sense. The FAA tells you to follow guidelines that pertain mainly to small aircraft. There is no use of the information for the tower, since they can't see you and can't call you back to give you instructions. Thus there's a high chance they'll just tell you not to mess around. Read the "pilots or operators" thread. We are not pilots until trained and permitted as such.
It is, because all manned aircraft in the airspace are talking to the control tower with some very limited exceptions. If ATC knows there is RC activity in a given area, they will warn pilots, generally by putting the information into the recorded ATIS broadcast that aircraft are supposed to listen to before entering the airspace and/or by directly warning the aircraft whose course will take them near the activity (something like "Use caution; model aircraft in use 3.5nm NE of airport at or below 500ft AGL"). They aren't likely to say no unless you're looking for something crazy like flying 1000ft AGL or want to fly in a really terrible spot (like 0.5 miles from the airport directly along a runway centerline where aircraft are coming in on final approach). If you have a flying field or the like they'll set up a Letter of Agreement with the club or group running it laying out the expected flight areas and simplifying the call to "turn on" that area of airspace.