Someone installed Firefox on a computer at a non-profit radio station I was involved with not so long ago. The owner of the station sent an email to all saying

Someone installed Firefox on a computer at a non-profit radio station I was involved with not so long ago. The owner of the station sent an email to all saying that if he found out who had installed the "firefox trojan" on the office PC, he would "sue them and call in the police". A few days later, all computers in the building had been downgraded from IE8 to IE6 and locked down so users couldn't even reboot. It's now official policy in that company that if anyone puts their own USB drive into an office computer, they'll be asked to leave the station. There is electrical tape stuck over the USB ports. That's the sort of mindless, dribbling paranoia you're up against.