Some retailers use Euclid Analytics, which uses the Wi-Fi antennas inside stores to see how many people are coming into a store, how long they stay and even which aisles they walk. It does this by using signals from each smartphone that comes near the store.
Any sensitive information that could be accessed by hackers should be encrypted, especially when communicating over wireless networks. Make sure to keep your private key confidential.
Schools have a responsibility to protect your information, but it can be vulnerable to release or data breaches. Be careful when giving out personal information and try to educate yourself on your rights as a student so that you can best protect yourself.
You are still being watched, and your data being collected, so be careful what you send and to where you send it too. Innocent messages sent out of the country can easily make you become a person of interest for no reason.