Thieves can break into remote controlled garage doors using similar technology.

My neighbor was robbed. They had a device which captured the garage door signal. Once in the garage they were able to break through the door between the garage and house and clean the place out. Oddly, they left the device ... which apparently is available online.

Of course, thieves have been able to steal passwords to web sites using packet sniffing software or other man in the middle attacks.