What frequency are these apps using? I haven't looked it up but I doubt most computer speakers go above 15Khz (why would they?) A young person should be able to hear really high but audible tones and an adult would rapidly lose the ability. If this is not the case it would make sense to set a limit on the tones such a device can send and receive. On the other hand there might be legitimate uses for such tech so maybe…
It's not exactly that straightforward. In general any modern audio equipment will run up to 20kHz since that's generally accepted as the range of human hearing. From what I can tell, the lowpass filters built in to equipment (eg antialiasing on ADC/DAC) attenuates starting at 19 or 20 kHz. But these are realized as low order physical filters, meaning they roll off slowly, so you'd have to start attenuating at something much lower to truly remove the 18-20 range. That would introduce distortion where the rolloff starts, which you probably don't want.