Even if it operates in the unlicensed freq. bands, ie ISM bands, there are still limitations to how much you may interfere with others, expressed in eg duty cyc

Even if it operates in the unlicensed freq. bands, ie ISM bands, there are still limitations to how much you may interfere with others, expressed in eg duty cycle requirements (ie not sending too long at a time) and energy levels (ie not sending too strong). That's what the FCC/ETSI/CE etc etc regulations do.