I think that there are different laws in different countries around Europe so it might not be illegal everywhere. For example:-

In France at the moment it is illegal to use a bluetooth device outside your own home.
In Ireland the iPod broadcaster (iPod on your car radio dohicky) is technically illegal.


To be honest though who will ever know. The signal strength on most of these units is so weak that they wouldn't be picked up by anyone unless they were specifically looking for them in the right area at the right time. (i.e. for the split second you push the button on the remote)

P.S. Sorry about the IR / RF error above. Had the wife in my ear while I was typing.