[Random link]: http://www.beeman.ca/sitebuildercontent/sitebuilderfiles/mob...
Also there has been a lot of usage of 2.4GHz devices in recent years.
bluetooth? - low power, doesn't travel far
wifi - been around long before 2005
cell phones - don't use 2.4 unless BT or wi-fi, have also been in the 1800/1900 gsm bands long before LTE/data networks
microwave ovens - been around forever.
Doesn't seem to add up.
not saying RF doesn't hurt, just playing devils advocate.