Yes, it is true that defeat magnets can be used...but it's not unique to surface RF and being visible, a small compass can find the magnets on any window and it's really doubtful that common installers use BMS' or magnaspheres (recently coming to market). This is where interior protection comes into play and having a system that has enough protection installed.
There's many ways to contact top and bottom sashes hardwired, however with RF, unless you have double the transmitters, that means that the transmitter and magnet are going to need to be installed on the meeting rail of the two sashes.
There's many ways to contact top and bottom sashes hardwired, however with RF, unless you have double the transmitters, that means that the transmitter and magnet are going to need to be installed on the meeting rail of the two sashes.