Not that I condone the wireless companies selling this kind of data, but if you're in a situation where a bounty hunter is after you, step one is don't carry a mobile phone.
The issue is that these tools 1- exist 2- aren't kept under the tightest lock and key possible. Because any schmuck can get access to them for the right price, nobody should have a cell phone if we put the onus on the victims.
Or an abusive partner..
For example, get involved in a messy divorce, get out-lawyered, end up on the hook for astronomical amounts of retroactive child support. If you're not careful you might be dealing with a lot more than just the repo man.
Plus the way the legal system is in the US, a single unpaid parking ticket could spiral completely out of control into tens of thousands in late payment fees, fines, and jail time.
The existence of bounty hunters is in some ways just a bizzare commercialisation of what should be a government function.
You can carry one if you don't use it to contact people you know. But of course you will, ignoring the advice from the tough guy that's trying to save you, according to every movie ever touching the subject.
More sophisticated attacks would identify your usage pattern, the date you bought the new phone, the train that sounds in the background or even the fact that you log in in your favourite cat videos site.