Every mobile operator has stories like this. Back in the GSM times the common theme in Europe was people using illegaly imported devices made for the US market.

Every mobile operator has stories like this. Back in the GSM times the common theme in Europe was people using illegaly imported devices made for the US market. The unlicensed 900 MHz band in the US fell right into the GSM band in Europe. Apparently the worst offenders were wireless security cameras.