I've two phones, one synced to the car's bluetooth system, the other - the punting phone - not, for obvious reasons.
The technology is getting too smart for many of us, and any punter who does not have a separate phone, that is protected by a lock code and kept hidden from a significant other, is asking for big trouble.
After every punt, I delete all text messages and call lists, and as a PAYG, has no bills or paper trail. It is funded from a separate online bank account too. As the phone is never backed up, has no music and not used for emails, I also do a full reset every now and then as an added security precaution.