And law enforcement, for better or worse, would like to know who is activating them, in case there is a problem like the London bombings, when they traced a subject to an address in Italy by his phone.
I have no doubt that if the gub'mint is interested in a person, they can listen in (even when they're not using the phone), track them and download all the pictures and address books in the phone. And probably a lot more we don't know about.
If I ever have to disappear, I will throw my cell phone in the lake and the battery in another lake before I leave.
Pre-paid phones are not exactly "new" to the network. It has already been commissioned, and in some cases activated. Other cases you scratch off the concealer, and punch in the code. You pays your money and it is ready to go. Overseas you stick in the SIM, enter the PIN and PUK, and go. It is all about automating the process so that you DO NOT have to go through some government beaurocrat. Law enforcement (in the US anyway) has this little thing about requiring a warrant to monitor your phone. LID, in Euprope, is different. I propose that if you want total law enforcement access for all of your telecommunications, the EU is for you. Me, I take my rights a lot more seriously.