No. Large open-air spaces overwhelm the IR signal. The reflective nature of this technology is ideal for standard classroom audio.
With RF technology, there is a limit depending on local interference and the number of systems desired. With IR technology, as long as the classrooms are enclosed, there is no limit to the number of systems you can have on one campus.
RF (radio frequency) technology uses radio waves to transit the audio signal. These are susceptible to RF interference. IR (infrared) technology used infrared light to carry the audio signal thus keeping the signal in the room and eliminating RF interference.