Paul has a Samsung Galaxy S3 and wants to enjoy all the apps her friends have, but is concerned about privacy. Leo says that while apps have access to things on her phone, it doesn't mean that it does anything with her personal details. Apps need access to certain parts of her phone to simply work. Unfortunately, it's not set up to be "granular" or specific with what things an app can or cannot have access to.
Should she feel safe that apps on Google Play have been "vetted?" Leo says yes. Apple probably is more strict, but Google does vet them and if there is one that's malicious, Google has a kill switch to take it off her phone. She should understand that the smartphone is the world's best spy device, though. The key is to make an informed choice, know what privacy she's giving up, and when. Most of the data that apps would be collecting from her are for advertising purposes, though.